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  • 7 Cool Firefox Ad-ons

    <b>The Linux Box:</b> "One of the coolest things about Firefox is its extensibility. Everyone has their collection of favorite Firefox add-ons and I thought I would share mine. Some provide improved organization, some have a certain "WOW!" factor, and others just look pretty."

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  • Wikimedia Commons not working properly from IE 8

    - by Johannes Rössel
    It happens fairly often that a page on Wikimedia Commons doesn't load in IE. This happens to me on both machines I use, each one Windows 7 with IE 8. The page just loads endlessly (or connects—can't really tell) and timeouts after a while. Repeated attempts (trying to load the same page in 5 to 10 tabs) sometimes work, but sometimes it takes a lot more tries. As far as I can tell, no other program is affected—Firefox or PowerShell have no trouble loading the page. Also, when I use Fiddler it seems to load fine on the first try as well. Anyone has an idea what might be going on? I didn't change any settings that I am aware of (and most likely didn't do so in the same way on both machines). Preemptive note: I don't need advice in the form of »Use another browser instead.«.

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  • Loading and unloading ISO files in Windows 8

    - by Mohd. Ismail
    I saw on one site that the new Windows 8 could load ISO images without the help of other programs. Is Windows 8 creating a new drive for every ISO? Or does it have one fake drive to load all ISOS in? How can I know if a file is really an ISO inside? Some PCs use UltraISO to open ISOs. If I just enter the ISO name in DOS, it is loading in UltraISO. How can I load the ISO only in Windows 8 on all PCs, whether they have UltraISO or not? How can I unload ISOs?

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  • Block spam by using geoip filter?

    - by faultyserver
    We are looking for a way to be able to block spam based on geographic location by filtering using geoip. context: we rarely have any email correspondence outside of the USA, so we would like to block all incoming email outside the US except for maybe one or two countries. After a little Googling I have found a couple of solutions that may work (or not), but I would like to know what other sysadmins are currently doing or what they would recommend as a solution. Here is what I have found so far: Using PowerDNS and its GeoIP backend it is possible to use geoip for filtering. Normally this backend is used to help distribute load as a kind of load balancing but I dont see why it couldnt be used to kill spam as well? Possibly use the Maxmind lite country database and some scripting to do a similar job. Ideally what I am looking for is a solution that would handle decent load and scale well too...aren't we all! ;) Thanks in advance for your help! :-)

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  • What to do for a 1 million concurrent web application? [duplicate]

    - by Amit Singh
    This question already has an answer here: How do you do load testing and capacity planning for web sites? 3 answers There are few things that I would like to know here. What server configuration do I need. And if I am deploying it on EC2 how many VMs do I need and what should be their configuration. What options do I have to do a load testing for 1 million concurrent users. Any pointer to (for php) how to code or what to keep in mind for such application. This is for sure that I don't exactly know what to ask because this is my first application on this scale. But one thing is clear that this application should pass a load test of 1 million concurrent request.

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  • Error using SoapClient() in PHP [migrated]

    - by Dhaval
    I'm trying to access WSDL(Web Service Definition Language) file using SoapClient() of PHP. I found that WSDL file is authenticated. I tried with passing credentials on an array by another parameter and active SSL on my server, still I'm getting an error. Here is the code I'm using: $client = new SoapClient("https://webservices.chargepointportal.net:8081/coulomb_api_1.1.wsdl",array("trace" = "1","Username" = "username","Password" = "password")); Here is the error I'm getting: Warning: SoapClient::SoapClient(https://webservices.chargepointportal.net:8081/coulomb_api_1.1.wsdl) [soapclient.soapclient]: failed to open stream: Connection timed out in PATH_TO_FILE on line 80 Warning: SoapClient::SoapClient() [soapclient.soapclient]: I/O warning : failed to load external entity "https://webservices.chargepointportal.net:8081/coulomb_api_1.1.wsdl" in PATH_TO_FILE on line 80 Fatal error: Uncaught SoapFault exception: [WSDL] SOAP-ERROR: Parsing WSDL: Couldn't load from 'https://webservices.chargepointportal.net:8081/coulomb_api_1.1.wsdl' : failed to load external entity "https://webservices.chargepointportal.net:8081/coulomb_api_1.1.wsdl" in PATH_TO_FILE:80 Stack trace: #0 /home2/wingstec/public_html/widget/API/index.php(80): SoapClient-SoapClient('https://webserv...', Array) #1 {main} thrown in PATH_TO_FILE on line 80 It seems that error says file not exist at the path we given but when we run that path directly on browser then we're getting that file Can anyone help me to figure out what the exactly problem is?

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  • Does Ubuntu run on current Asus Transformer Prime?

    - by Ubuntu User
    I've read instructions about dual boot Android / Transformer Prime (a significant factor in ordering one). Also about not working with /latest/ Transformer Prime (firmware / BIOS?) Also about imminent Ubuntu ARM support. Will I be able to run Ubuntu in a day or two when Transformer arrives? Also, am I right to assume I can restore Transformer to factory status if I break something in the attempt?

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  • Linking Secrets - Part I - Linking Structure

    Google classes a link as a 'vote' for your website, as most people only link to a site if they are talking about it or referring to it as a good resource. This means the almighty link has become a huge factor in how well you rank in the search engines.

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  • The Best How-To Geek Articles for June 2012

    - by Asian Angel
    This past month we covered topics such as why you only have to wipe a disk once to erase it, what RSS is and how you can benefit from using it, how websites are tracking you online, and more. Join us as we look back at the best articles for June. How to Banish Duplicate Photos with VisiPic How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It?

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  • nginx+php-fpm help optimize configs

    - by Dmitro
    I have 3 servers. First server (CPU - model name: 06/17, 2.66GHz, 4 cores, 8GB RAM) have nginx as load balancer with next config upstream lb_mydomain { server mydomain.ru:81 weight=2; server 66.0.0.18 weight=6; } server { listen 80; server_name ~(?!mydomain.ru)(.*); client_max_body_size 20m; location / { proxy_pass http://lb_mydomain; proxy_redirect off; proxy_set_header Connection close; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_pass_header Set-Cookie; proxy_pass_header P3P; proxy_pass_header Content-Type; proxy_pass_header Content-Disposition; proxy_pass_header Content-Length; } } And configs from nginx.conf: user www-data; worker_processes 5; # worker_priority -1; error_log /var/log/nginx/error.log; pid /var/run/nginx.pid; events { worker_connections 5024; # multi_accept on; } http { include /etc/nginx/mime.types; access_log /var/log/nginx/access.log; sendfile on; default_type application/octet-stream; #tcp_nopush on; keepalive_timeout 65; tcp_nodelay on; gzip on; gzip_disable "MSIE [1-6]\.(?!.*SV1)"; # PHP-FPM (backend) upstream php-fpm { server 127.0.0.1:9000; } include /etc/nginx/conf.d/*.conf; include /etc/nginx/sites-enabled/*; } And config php-fpm: listen = 127.0.0.1:9000 ;listen.backlog = -1 ;listen.allowed_clients = 127.0.0.1 ;listen.owner = www-data ;listen.group = www-data ;listen.mode = 0666 user = www-data group = www-data pm = dynamic pm.max_children = 80 ;pm.start_servers = 20 pm.min_spare_servers = 5 pm.max_spare_servers = 35 ;pm.max_requests = 500 pm.status_path = /status ping.path = /ping ;ping.response = pong request_terminate_timeout = 30s request_slowlog_timeout = 10s slowlog = /var/log/php-fpm.log.slow ;rlimit_files = 1024 ;rlimit_core = 0 ;chroot = chdir = /var/www ;catch_workers_output = yes ;env[HOSTNAME] = $HOSTNAME ;env[PATH] = /usr/local/bin:/usr/bin:/bin ;env[TMP] = /tmp ;env[TMPDIR] = /tmp ;env[TEMP] = /tmp ;php_admin_value[sendmail_path] = /usr/sbin/sendmail -t -i -f [email protected] ;php_flag[display_errors] = off ;php_admin_value[error_log] = /var/log/fpm-php.www.log ;php_admin_flag[log_errors] = on ;php_admin_value[memory_limit] = 32M In top I see 20 php-fpm processes which use from 1% - 15% CPU. So it's have high load averadge: top - 15:36:22 up 34 days, 20:54, 1 user, load average: 5.98, 7.75, 8.78 Tasks: 218 total, 1 running, 217 sleeping, 0 stopped, 0 zombie Cpu(s): 34.1%us, 3.2%sy, 0.0%ni, 37.0%id, 24.8%wa, 0.0%hi, 0.9%si, 0.0%st Mem: 8183228k total, 7538584k used, 644644k free, 351136k buffers Swap: 9936892k total, 14636k used, 9922256k free, 990540k cached Second server(CPU - model name: Intel(R) Xeon(R) CPU E5504 @ 2.00GHz, 8 cores, 8GB RAM). Nginx configs from nginx.conf: user www-data; worker_processes 5; # worker_priority -1; error_log /var/log/nginx/error.log; pid /var/run/nginx.pid; events { worker_connections 5024; # multi_accept on; } http { include /etc/nginx/mime.types; access_log /var/log/nginx/access.log; sendfile on; default_type application/octet-stream; #tcp_nopush on; keepalive_timeout 65; tcp_nodelay on; gzip on; gzip_disable "MSIE [1-6]\.(?!.*SV1)"; # PHP-FPM (backend) upstream php-fpm { server 127.0.0.1:9000; } include /etc/nginx/conf.d/*.conf; include /etc/nginx/sites-enabled/*; } And config of php-fpm: listen = 127.0.0.1:9000 ;listen.backlog = -1 ;listen.allowed_clients = 127.0.0.1 ;listen.owner = www-data ;listen.group = www-data ;listen.mode = 0666 user = www-data group = www-data pm = dynamic pm.max_children = 50 ;pm.start_servers = 20 pm.min_spare_servers = 5 pm.max_spare_servers = 35 ;pm.max_requests = 500 ;pm.status_path = /status ;ping.path = /ping ;ping.response = pong ;request_terminate_timeout = 0 ;request_slowlog_timeout = 0 ;slowlog = /var/log/php-fpm.log.slow ;rlimit_files = 1024 ;rlimit_core = 0 ;chroot = chdir = /var/www ;catch_workers_output = yes ;env[HOSTNAME] = $HOSTNAME ;env[PATH] = /usr/local/bin:/usr/bin:/bin ;env[TMP] = /tmp ;env[TMPDIR] = /tmp ;env[TEMP] = /tmp ;php_admin_value[sendmail_path] = /usr/sbin/sendmail -t -i -f [email protected] ;php_flag[display_errors] = off ;php_admin_value[error_log] = /var/log/fpm-php.www.log ;php_admin_flag[log_errors] = on ;php_admin_value[memory_limit] = 32M In top I see 50 php-fpm processes which use from 10% - 25% CPU. So it's have high load averadge: top - 15:53:05 up 33 days, 1:15, 1 user, load average: 41.35, 40.28, 39.61 Tasks: 239 total, 40 running, 199 sleeping, 0 stopped, 0 zombie Cpu(s): 96.5%us, 3.1%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.4%si, 0.0%st Mem: 8185560k total, 7804224k used, 381336k free, 161648k buffers Swap: 19802108k total, 16k used, 19802092k free, 5068112k cached Third server is server with database postgresql. Also i try ab -n 50 -c 5 http://www.mydomain.ru/ And I get next info: Complete requests: 50 Failed requests: 48 (Connect: 0, Receive: 0, Length: 48, Exceptions: 0) Write errors: 0 Total transferred: 9271367 bytes HTML transferred: 9247767 bytes Requests per second: 1.02 [#/sec] (mean) Time per request: 4882.427 [ms] (mean) Time per request: 976.486 [ms] (mean, across all concurrent requests) Transfer rate: 185.44 [Kbytes/sec] received Please advise how can I make lower level of load average?

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  • Aptronyms: fitting the profession to the name

    - by Tony Davis
    Writing a recent piece on the pains of index fragmentation, I found myself wondering why, in SQL Server, you can’t set the equivalent of a fill factor, on a heap table. I scratched my head…who might know? Phil Factor, of course! I approached him with a due sense of optimism only to find that not only did he not know, he also didn’t seem to care much either. I skulked off thinking how this may be the final nail in the coffin of nominative determinism. I’ve always wondered if there was anything in it, though. If your surname is Plumb or Leeks, is there even a tiny, extra percentage chance that you’ll end up fitting bathrooms? Some examples are quite common. I’m sure we’ve all met teachers called English or French, or lawyers called Judge or Laws. I’ve also known a Doctor called Coffin, a Urologist called Waterfall, and a Dentist called Dentith. Two personal favorites are Wolfgang Wolf who ended up managing the German Soccer team, Wolfsburg, and Edmund Akenhead, a Crossword Editor for The Times newspaper. Having forgiven Phil his earlier offhandedness, I asked him for if he knew of any notable examples. He had met the famous Dr. Batty and Dr. Nutter, both Psychiatrists, knew undertakers called Death and Stiff, had read a book by Frederick Page-Turner, and suppressed a giggle at the idea of a feminist called Gurley-Brown. He even managed to better my Urologist example, citing the article on incontinence in the British Journal of Urology (vol.49, pp.173-176, 1977) by A. J. Splatt and D. Weedon. What, however, if you were keen to gently nudge your child down the path to a career in IT? What name would you choose? Subtlety probably doesn’t really work, although in a recent interview, Rodney Landrum did congratulate PowerShell MVP Max Trinidad on being named after a SQL function. Grant “The Memory” Fritchey (OK, I made up that nickname) doesn’t do badly either. Some surnames, seem to offer a natural head start, although I know of no members of the Page-Reid clan in the profession. There are certainly families with the Table surname, although sadly, Little Bobby Tables was merely a legend by xkcd. A member of the well-known Key family would need to name their son Primary, or maybe live abroad, to make their mark. Nominate your examples of people seemingly destined, by name, for their chosen profession (extra points for IT). The best three will receive a prize. Cheers, Tony.

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  • SQL Rally Pre-Con: Data Warehouse Modeling – Making the Right Choices

    - by Davide Mauri
    As you may have already learned from my old post or Adam’s or Kalen’s posts, there will be two SQL Rally in North Europe. In the Stockholm SQL Rally, with my friend Thomas Kejser, I’ll be delivering a pre-con on Data Warehouse Modeling: Data warehouses play a central role in any BI solution. It's the back end upon which everything in years to come will be created. For this reason, it must be rock solid and yet flexible at the same time. To develop such a data warehouse, you must have a clear idea of its architecture, a thorough understanding of the concepts of Measures and Dimensions, and a proven engineered way to build it so that quality and stability can go hand-in-hand with cost reduction and scalability. In this workshop, Thomas Kejser and Davide Mauri will share all the information they learned since they started working with data warehouses, giving you the guidance and tips you need to start your BI project in the best way possible?avoiding errors, making implementation effective and efficient, paving the way for a winning Agile approach, and helping you define how your team should work so that your BI solution will stand the test of time. You'll learn: Data warehouse architecture and justification Agile methodology Dimensional modeling, including Kimball vs. Inmon, SCD1/SCD2/SCD3, Junk and Degenerate Dimensions, and Huge Dimensions Best practices, naming conventions, and lessons learned Loading the data warehouse, including loading Dimensions, loading Facts (Full Load, Incremental Load, Partitioned Load) Data warehouses and Big Data (Hadoop) Unit testing Tracking historical changes and managing large sizes With all the Self-Service BI hype, Data Warehouse is become more and more central every day, since if everyone will be able to analyze data using self-service tools, it’s better for him/her to rely on correct, uniform and coherent data. Already 50 people registered from the workshop and seats are limited so don’t miss this unique opportunity to attend to this workshop that is really a unique combination of years and years of experience! http://www.sqlpass.org/sqlrally/2013/nordic/Agenda/PreconferenceSeminars.aspx See you there!

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  • Migrating BizTalk 2006 R2 to BizTalk 2010 XLANGs Issue

    - by SURESH GIRIRAJAN
    When we migrate some BizTalk apps from BizTalk 2006 R2 to BizTalk 2010, and we ran into issue when a .net component called inside the orchestration. In the .net component we are trying to retrieve some promoted property and we also checked in the BizTalk group hub to validate it was promoted, no issues there.  Only when we try to access the data into the .net component we had issue. We just moved all the assembly what we had in BizTalk 2006 R2 to BizTalk 2010, didn’t recompile anything in BizTalk 2010 environment. But looking further there is couple of new namespace added to the Microsoft.XLANGs… in BizTalk 2010 compared to BizTalk 2006 R2 caused the issue. So all we did to fix the issue is recompile the project in 2010 environment and it worked fine. So it looks like some backward compatibility issue.  public static void Load(XLANGMessage msg) {  try  {      // get the process id from context.       object ctxVal = msg.GetPropertyValue(typeof(ProcessID)); … } BizTalk 2010: Error Message in the event viewer:  The service instance will remain suspended until administratively resumed or terminated. If resumed the instance will continue from its last persisted state and may re-throw the same unexpected exception. InstanceId: 441d73d3-2e84-49d2-b6bd-7218065b5e1d Shape name: Bulk Load ShapeId: bb959e56-9221-48be-a80f-24051196617d Exception thrown from: segment 1, progress 65 Inner exception: A property cannot be associated with the type 'Tellago.Common.Schemas.ProcessId'.   Exception type: InvalidPropertyTypeException Source: Microsoft.XLANGs.Engine Target Site: Microsoft.XLANGs.RuntimeTypes.MessagePropertyDefinition _getMessagePropertyDefinition(System.Type) The following is a stack trace that identifies the location where the exception occured   at Microsoft.XLANGs.Core.XMessage._getMessagePropertyDefinition(Type propType) at Microsoft.XLANGs.Core.XMessage.GetContentProperty(Type propType) at Microsoft.XLANGs.Core.XMessage.GetPropertyValue(Type propType) at Microsoft.BizTalk.XLANGs.BTXEngine.BTXMessage.GetPropertyValue(Type propType) at Microsoft.XLANGs.Core.MessageWrapperForUserCode.GetPropertyValue(Type propType) at Tellago.Common.Components.Load(XLANGMessage msg) at Tellago.SuspensionProcess.segment1(StopConditions stopOn) at Microsoft.XLANGs.Core.SegmentScheduler.RunASegment(Segment s, StopConditions stopCond, Exception& exp)

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  • IIS8 Memory Improvements

    - by The Official Microsoft IIS Site
    There is a lot of buzz in the Internet Information Services (IIS) community about IIS 8, the version of IIS that is included with Windows Server 2012. While there are plenty of new features in IIS 8, for this writing I am going to focus on the memory improvements that you will see for the application pools. Memory is a key resource on an IIS server as it is often the first limiting factor if you planned your CPU and disk requirements appropriately. I was fortunate to be able to attend TechEd North...(read more)

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  • Efficient SQL Server Indexing by Design

    Having a good set of indexes on your SQL Server database is critical to performance. Efficient indexes don't happen by accident; they are designed to be efficient. Greg Larsen discusses whether primary keys should be clustered, when to use filtered indexes and what to consider when using the Fill Factor.

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  • Finding Stuff in SQL Server Database DDL

    You'd have thought that nothing would be easier than using SQL Server Management Studio (SSMS) for searching through the DDL for both the names and definitions of the structural metadata of your databases, for the occurrence of a particular string of letters. Not so easy, it turns out, though Phil Factor is able to come up with various methods for various purposes.

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  • Service Testing made easy with SO-Aware Test Workbench

    - by cibrax
    I happy to announce today a new addition to our SO-Aware service repository toolset, SO-Aware Test Workbench, a WPF desktop application for doing functional and load testing against existing WCF Services. This tool is completely integrated to the SO-Aware service repository, which makes configuring new load and functional tests for WCF Soap and REST services a breeze. From now on, the service repository can play a very important role in an organization by facilitating collaboration between developers and testers. Developers can create and register new services in the repository with all the related artifacts like configuration. On the other hand, Testers can just pick one of the existing services in the repository and create functional or load tests from there, with no need to deal with specific details of the service implementation, location or configuration settings. Developers and Testers can later use the result of those tests to modify the services or adjust different settings on the tests or service configuration. Gustavo Machado, one of the developers behind this project, has written an excellent post describing all the functionality that can find today in the tool. You can also see the tool in action in this Endpoint Tv episode with Jesus and Ron Jacobs.

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  • Data indexing frameworks fit for large E-Commerce applications

    - by Dabu
    we wrote and still maintain a large E-Commerce application. Our feature list resembles what you would expect from most shops. We'd like to improve some of our features, and now the search/suggestion list functionality (enter some letters, a JScripted suggestion list appears) has caught our eye. Currently, we use http://xapian.org/. It has some drawbacks. Firstly, it's not actually the right solution. It has been created to index documents, not ever-changing data in a granularity that an E-Commerce application would need. Secondly, the load on the database is significant when we reindex all data every night. We'd like a framework that has been designed for indexing database data, which can add to the index easily and without much load, which can supply data changes in the backoffice quickly to the frontend without much load and delay. I'm aware of the fact that Xapian is Open Source and even Free Software, so we could adapt it to our needs if we decided to invest the time and manpower. But taking a quick look around for a solution more suited seems fair, right? Oh, and commercial applications are fine, too. FOSS is not required. Thanks a bunch.

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  • DB2 LUW tools for diagnosing issues when the stuff hits the fan

    - by Ichorus
    I am no DBA and very much a novice when it comes to DB2 so even 'obvious' answers are welcome to this question: I love db2top but sometimes I cannot get it to run if the load average is high on a db2 LUW. This morning I was looking at an issue where load average shot up suddenly, I could not get db2top to come up and I needed to find out what was happening. What can I do to find out who is doing what in this situation? I suspected a horribly bad query was being run by someone...is there a good way to find information on poor performing SQL on the fly in that type of situation? Are there any good ways to collect good, actionable stats who/where bad sql is coming from in the event that load average is so high? I know about db2pd but I am not sure how to use it effectively and slogging through tens of thousands of lines of raw data is probably not the most efficient way to get at the heart of a problem. Any tips or resources?

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  • Blank Screen at boot Ubuntu 12.04 - nvidia-current - Macbook Air 3,2

    - by soulnafein
    I've installed nvidia-current using the Additional Drivers application in Ubuntu 12.04. I need those drivers so I can use accelerated WebGL. After installing the drivers, and rebooting X fails to start and I have a frozen system/dark screen. Below is the content of Xorg.0.log How can I fix this problem? [ 4.666] X.Org X Server 1.11.3 Release Date: 2011-12-16 [ 4.666] X Protocol Version 11, Revision 0 [ 4.666] Build Operating System: Linux 2.6.42-23-generic x86_64 Ubuntu [ 4.666] Current Operating System: Linux david-macbook-air 3.2.0-34-generic #53-Ubuntu SMP Thu Nov 15 10:48:16 UTC 2012 x86_64 [ 4.666] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.2.0-34-generic root=UUID=b3d5ae2a-72af-4ef9-b775-0d40b5f80f9b ro quiet splash vt.handoff=7 [ 4.666] Build Date: 29 August 2012 12:12:33AM [ 4.666] xorg-server 2:1.11.4-0ubuntu10.8 (For technical support please see http://www.ubuntu.com/support) [ 4.666] Current version of pixman: 0.24.4 [ 4.666] Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. [ 4.666] Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. [ 4.666] (==) Log file: "/var/log/Xorg.0.log", Time: Thu Dec 13 10:18:02 2012 [ 4.668] (==) Using system config directory "/usr/share/X11/xorg.conf.d" [ 4.668] (==) No Layout section. Using the first Screen section. [ 4.668] (==) No screen section available. Using defaults. [ 4.668] (**) |-->Screen "Default Screen Section" (0) [ 4.668] (**) | |-->Monitor "<default monitor>" [ 4.668] (==) No monitor specified for screen "Default Screen Section". Using a default monitor configuration. [ 4.668] (==) Automatically adding devices [ 4.668] (==) Automatically enabling devices [ 4.668] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist. [ 4.668] Entry deleted from font path. [ 4.668] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist. [ 4.668] Entry deleted from font path. [ 4.669] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist. [ 4.669] Entry deleted from font path. [ 4.669] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist. [ 4.669] Entry deleted from font path. [ 4.669] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist. [ 4.669] Entry deleted from font path. [ 4.669] (WW) The directory "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType" does not exist. [ 4.669] Entry deleted from font path. [ 4.669] (==) FontPath set to: /usr/share/fonts/X11/misc, /usr/share/fonts/X11/Type1, built-ins [ 4.669] (==) ModulePath set to "/usr/lib/x86_64-linux-gnu/xorg/extra-modules,/usr/lib/xorg/extra-modules,/usr/lib/xorg/modules" [ 4.669] (II) The server relies on udev to provide the list of input devices. If no devices become available, reconfigure udev or disable AutoAddDevices. [ 4.669] (II) Loader magic: 0x7f6222467b00 [ 4.669] (II) Module ABI versions: [ 4.669] X.Org ANSI C Emulation: 0.4 [ 4.669] X.Org Video Driver: 11.0 [ 4.669] X.Org XInput driver : 16.0 [ 4.669] X.Org Server Extension : 6.0 [ 4.670] (--) PCI:*(0:2:0:0) 10de:08a3:106b:00d3 rev 162, Mem @ 0x92000000/16777216, 0x80000000/268435456, 0x90000000/33554432, I/O @ 0x00001000/128, BIOS @ 0x????????/131072 [ 4.670] (II) Open ACPI successful (/var/run/acpid.socket) [ 4.670] (II) LoadModule: "extmod" [ 4.671] (II) Loading /usr/lib/xorg/modules/extensions/libextmod.so [ 4.671] (II) Module extmod: vendor="X.Org Foundation" [ 4.671] compiled for 1.11.3, module version = 1.0.0 [ 4.671] Module class: X.Org Server Extension [ 4.671] ABI class: X.Org Server Extension, version 6.0 [ 4.671] (II) Loading extension MIT-SCREEN-SAVER [ 4.671] (II) Loading extension XFree86-VidModeExtension [ 4.671] (II) Loading extension XFree86-DGA [ 4.671] (II) Loading extension DPMS [ 4.671] (II) Loading extension XVideo [ 4.671] (II) Loading extension XVideo-MotionCompensation [ 4.671] (II) Loading extension X-Resource [ 4.671] (II) LoadModule: "dbe" [ 4.671] (II) Loading /usr/lib/xorg/modules/extensions/libdbe.so [ 4.671] (II) Module dbe: vendor="X.Org Foundation" [ 4.671] compiled for 1.11.3, module version = 1.0.0 [ 4.671] Module class: X.Org Server Extension [ 4.671] ABI class: X.Org Server Extension, version 6.0 [ 4.671] (II) Loading extension DOUBLE-BUFFER [ 4.671] (II) LoadModule: "glx" [ 4.671] (II) Loading /usr/lib/x86_64-linux-gnu/xorg/extra-modules/libglx.so [ 4.869] (II) Module glx: vendor="NVIDIA Corporation" [ 4.869] compiled for 4.0.2, module version = 1.0.0 [ 4.869] Module class: X.Org Server Extension [ 4.869] (II) NVIDIA GLX Module 295.40 Thu Apr 5 21:57:38 PDT 2012 [ 4.869] (II) Loading extension GLX [ 4.869] (II) LoadModule: "record" [ 4.870] (II) Loading /usr/lib/xorg/modules/extensions/librecord.so [ 4.870] (II) Module record: vendor="X.Org Foundation" [ 4.870] compiled for 1.11.3, module version = 1.13.0 [ 4.870] Module class: X.Org Server Extension [ 4.870] ABI class: X.Org Server Extension, version 6.0 [ 4.870] (II) Loading extension RECORD [ 4.870] (II) LoadModule: "dri" [ 4.870] (II) Loading /usr/lib/xorg/modules/extensions/libdri.so [ 4.870] (II) Module dri: vendor="X.Org Foundation" [ 4.870] compiled for 1.11.3, module version = 1.0.0 [ 4.870] ABI class: X.Org Server Extension, version 6.0 [ 4.870] (II) Loading extension XFree86-DRI [ 4.870] (II) LoadModule: "dri2" [ 4.871] (II) Loading /usr/lib/xorg/modules/extensions/libdri2.so [ 4.871] (II) Module dri2: vendor="X.Org Foundation" [ 4.871] compiled for 1.11.3, module version = 1.2.0 [ 4.871] ABI class: X.Org Server Extension, version 6.0 [ 4.871] (II) Loading extension DRI2 [ 4.871] (==) Matched nvidia as autoconfigured driver 0 [ 4.871] (==) Matched nouveau as autoconfigured driver 1 [ 4.871] (==) Matched nv as autoconfigured driver 2 [ 4.871] (==) Matched vesa as autoconfigured driver 3 [ 4.871] (==) Matched fbdev as autoconfigured driver 4 [ 4.871] (==) Assigned the driver to the xf86ConfigLayout [ 4.871] (II) LoadModule: "nvidia" [ 4.871] (II) Loading /usr/lib/x86_64-linux-gnu/xorg/extra-modules/nvidia_drv.so [ 4.887] (II) Module nvidia: vendor="NVIDIA Corporation" [ 4.887] compiled for 4.0.2, module version = 1.0.0 [ 4.887] Module class: X.Org Video Driver [ 4.892] (II) LoadModule: "nouveau" [ 4.894] (II) Loading /usr/lib/xorg/modules/drivers/nouveau_drv.so [ 4.894] (II) Module nouveau: vendor="X.Org Foundation" [ 4.894] compiled for 1.11.3, module version = 1.0.2 [ 4.894] Module class: X.Org Video Driver [ 4.894] ABI class: X.Org Video Driver, version 11.0 [ 4.894] (II) LoadModule: "nv" [ 4.895] (WW) Warning, couldn't open module nv [ 4.895] (II) UnloadModule: "nv" [ 4.895] (II) Unloading nv [ 4.895] (EE) Failed to load module "nv" (module does not exist, 0) [ 4.895] (II) LoadModule: "vesa" [ 4.895] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so [ 4.896] (II) Module vesa: vendor="X.Org Foundation" [ 4.896] compiled for 1.11.3, module version = 2.3.0 [ 4.896] Module class: X.Org Video Driver [ 4.896] ABI class: X.Org Video Driver, version 11.0 [ 4.896] (II) LoadModule: "fbdev" [ 4.896] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so [ 4.896] (II) Module fbdev: vendor="X.Org Foundation" [ 4.896] compiled for 1.11.3, module version = 0.4.2 [ 4.896] ABI class: X.Org Video Driver, version 11.0 [ 4.896] (==) Matched nvidia as autoconfigured driver 0 [ 4.896] (==) Matched nouveau as autoconfigured driver 1 [ 4.896] (==) Matched nv as autoconfigured driver 2 [ 4.896] (==) Matched vesa as autoconfigured driver 3 [ 4.896] (==) Matched fbdev as autoconfigured driver 4 [ 4.896] (==) Assigned the driver to the xf86ConfigLayout [ 4.896] (II) LoadModule: "nvidia" [ 4.896] (II) Loading /usr/lib/x86_64-linux-gnu/xorg/extra-modules/nvidia_drv.so [ 4.896] (II) Module nvidia: vendor="NVIDIA Corporation" [ 4.896] compiled for 4.0.2, module version = 1.0.0 [ 4.896] Module class: X.Org Video Driver [ 4.896] (II) UnloadModule: "nvidia" [ 4.896] (II) Unloading nvidia [ 4.896] (II) Failed to load module "nvidia" (already loaded, 32610) [ 4.896] (II) LoadModule: "nouveau" [ 4.897] (II) Loading /usr/lib/xorg/modules/drivers/nouveau_drv.so [ 4.897] (II) Module nouveau: vendor="X.Org Foundation" [ 4.897] compiled for 1.11.3, module version = 1.0.2 [ 4.897] Module class: X.Org Video Driver [ 4.897] ABI class: X.Org Video Driver, version 11.0 [ 4.897] (II) UnloadModule: "nouveau" [ 4.897] (II) Unloading nouveau [ 4.897] (II) Failed to load module "nouveau" (already loaded, 32610) [ 4.897] (II) LoadModule: "nv" [ 4.897] (WW) Warning, couldn't open module nv [ 4.897] (II) UnloadModule: "nv" [ 4.897] (II) Unloading nv [ 4.897] (EE) Failed to load module "nv" (module does not exist, 0) [ 4.897] (II) LoadModule: "vesa" [ 4.898] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so [ 4.898] (II) Module vesa: vendor="X.Org Foundation" [ 4.898] compiled for 1.11.3, module version = 2.3.0 [ 4.898] Module class: X.Org Video Driver [ 4.898] ABI class: X.Org Video Driver, version 11.0 [ 4.898] (II) UnloadModule: "vesa" [ 4.898] (II) Unloading vesa [ 4.898] (II) Failed to load module "vesa" (already loaded, 0) [ 4.898] (II) LoadModule: "fbdev" [ 4.898] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so [ 4.898] (II) Module fbdev: vendor="X.Org Foundation" [ 4.898] compiled for 1.11.3, module version = 0.4.2 [ 4.898] ABI class: X.Org Video Driver, version 11.0 [ 4.898] (II) UnloadModule: "fbdev" [ 4.898] (II) Unloading fbdev [ 4.899] (II) Failed to load module "fbdev" (already loaded, 0) [ 4.899] (II) NVIDIA dlloader X Driver 295.40 Thu Apr 5 21:38:35 PDT 2012 [ 4.899] (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs [ 4.899] (II) NOUVEAU driver Date: Wed Sep 12 13:42:43 2012 +0200 [ 4.899] (II) NOUVEAU driver for NVIDIA chipset families : [ 4.899] RIVA TNT (NV04) [ 4.899] RIVA TNT2 (NV05) [ 4.899] GeForce 256 (NV10) [ 4.899] GeForce 2 (NV11, NV15) [ 4.899] GeForce 4MX (NV17, NV18) [ 4.899] GeForce 3 (NV20) [ 4.900] GeForce 4Ti (NV25, NV28) [ 4.900] GeForce FX (NV3x) [ 4.900] GeForce 6 (NV4x) [ 4.900] GeForce 7 (G7x) [ 4.900] GeForce 8 (G8x) [ 4.900] GeForce GTX 200 (NVA0) [ 4.900] GeForce GTX 400 (NVC0) [ 4.900] (II) VESA: driver for VESA chipsets: vesa [ 4.900] (II) FBDEV: driver for framebuffer: fbdev [ 4.900] (++) using VT number 7 [ 4.902] (II) Loading sub module "fb" [ 4.902] (II) LoadModule: "fb" [ 4.902] (II) Loading /usr/lib/xorg/modules/libfb.so [ 4.902] (II) Module fb: vendor="X.Org Foundation" [ 4.902] compiled for 1.11.3, module version = 1.0.0 [ 4.902] ABI class: X.Org ANSI C Emulation, version 0.4 [ 4.902] (II) Loading sub module "wfb" [ 4.902] (II) LoadModule: "wfb" [ 4.903] (II) Loading /usr/lib/xorg/modules/libwfb.so [ 4.905] (II) Module wfb: vendor="X.Org Foundation" [ 4.905] compiled for 1.11.3, module version = 1.0.0 [ 4.905] ABI class: X.Org ANSI C Emulation, version 0.4 [ 4.905] (II) Loading sub module "ramdac" [ 4.905] (II) LoadModule: "ramdac" [ 4.905] (II) Module "ramdac" already built-in [ 4.907] (II) Loading /usr/lib/x86_64-linux-gnu/xorg/extra-modules/nvidia_drv.so [ 4.907] (II) Loading /usr/lib/xorg/modules/libwfb.so [ 4.907] (II) Loading /usr/lib/xorg/modules/libfb.so [ 4.912] (WW) Falling back to old probe method for vesa [ 4.912] (WW) Falling back to old probe method for fbdev [ 4.912] (II) Loading sub module "fbdevhw" [ 4.912] (II) LoadModule: "fbdevhw" [ 4.912] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so [ 4.912] (II) Module fbdevhw: vendor="X.Org Foundation" [ 4.912] compiled for 1.11.3, module version = 0.0.2 [ 4.912] ABI class: X.Org Video Driver, version 11.0 [ 4.912] (II) NVIDIA(0): Creating default Display subsection in Screen section "Default Screen Section" for depth/fbbpp 24/32 [ 4.912] (==) NVIDIA(0): Depth 24, (==) framebuffer bpp 32 [ 4.912] (==) NVIDIA(0): RGB weight 888 [ 4.912] (==) NVIDIA(0): Default visual is TrueColor [ 4.912] (==) NVIDIA(0): Using gamma correction (1.0, 1.0, 1.0) [ 4.912] (**) NVIDIA(0): Enabling 2D acceleration [ 5.442] (EE) NVIDIA(0): Failed to initialize the display subsystem for the NVIDIA [ 5.442] (EE) NVIDIA(0): graphics device! [ 5.442] (EE) NVIDIA(0): Failed to get supported display device(s) [ 5.442] (EE) NVIDIA(0): Failed to initialize dac HAL [ 5.442] (II) UnloadModule: "nvidia" [ 5.442] (II) Unloading nvidia [ 5.442] (II) UnloadModule: "wfb" [ 5.442] (II) Unloading wfb [ 5.442] (II) UnloadModule: "fb" [ 5.443] (II) Unloading fb [ 5.443] (EE) Screen(s) found, but none have a usable configuration. [ 5.443] Fatal server error: [ 5.443] no screens found [ 5.443] Please consult the The X.Org Foundation support at http://wiki.x.org for help. [ 5.443] Please also check the log file at "/var/log/Xorg.0.log" for additional information. [ 5.443] [ 5.447] ddxSigGiveUp: Closing log [ 5.447] Server terminated with error (1). Closing log file.

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  • Weird internet connection behavior

    - by ShadowBroker
    I'm having a strange problem with my internet connection. At the moment my ISP is Fastweb (an italian provider) and i noticed that sometimes i can't load some sites, then all i have to do is wait 5 minutes and then i can load the site again. Some other times, instead, images won't load on certains sites (this always happens with 500px.com or Facebook rarely). I noticed that if i use VPN software like Privitize VPN or Spotflux everything works like a charm. Is something wrong with my internet configuration? Thank you.

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  • my webserver with 16GB ram shows all RAM as used, but is it really, see the 'top'

    - by Alex
    I have some questions about my web server. Its a LAMP web server running centos 5.5 and php5, mysql5. The server gets hundreds (maybe thousand) of concurrent users during peak hours. I'm trying to optimize a little and understand "top". From what I can see: all 16GB of my ram have been used up? does that mean that my server needs more memory? My swap is only 2GB, should it be increased? usually during peak hours my server load average first number is about 2.5-3. What could I do to optimize the server so that the load average even during peak doesn't go above 1? In the past I was told a good working server should stay under 1 load, is this still true? Although even during load of 2.5-3, server pages and applications seem to load with pretty good speed. what should the memory size in php.ini be set to? top - 14:30:18 up 2 days, 12:41, 5 users, load average: 1.25, 1.74, 2.92 Tasks: 305 total, 2 running, 302 sleeping, 0 stopped, 1 zombie Cpu(s): 6.3%us, 0.9%sy, 0.0%ni, 92.5%id, 0.2%wa, 0.0%hi, 0.1%si, 0.0%st Mem: 16427200k total, 16111472k used, 315728k free, 3120316k buffers Swap: 2104496k total, 268k used, 2104228k free, 6216756k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 29080 apache 15 0 358m 36m 5192 S 20.2 0.2 2:08.40 httpd 29093 apache 18 0 357m 36m 5192 S 18.2 0.2 2:02.52 httpd 29079 apache 15 0 370m 49m 5832 S 10.0 0.3 2:32.14 httpd 1812 apache 15 0 370m 49m 5196 S 7.3 0.3 2:25.30 httpd 5204 apache 15 0 358m 36m 5168 S 5.3 0.2 0:59.28 httpd 29075 apache 15 0 370m 48m 5184 S 3.3 0.3 2:15.93 httpd 9712 apache 15 0 360m 38m 5180 S 3.0 0.2 0:54.81 httpd 29072 apache 16 0 358m 36m 5192 S 2.7 0.2 2:24.43 httpd 6310 apache 17 0 388m 67m 5180 S 2.3 0.4 0:58.85 httpd 8674 apache 15 0 343m 21m 4980 S 2.0 0.1 0:07.91 httpd 29085 apache 15 0 371m 49m 5224 S 2.0 0.3 2:16.86 httpd 29083 apache 15 0 370m 48m 5196 S 1.7 0.3 2:10.64 httpd 5575 apache 15 0 357m 36m 5228 S 1.3 0.2 0:53.78 httpd 29066 apache 15 0 379m 59m 5860 R 1.3 0.4 2:11.93 httpd 29078 apache 15 0 370m 48m 5188 S 1.3 0.3 2:14.52 httpd 29084 apache 15 0 370m 48m 5208 S 1.0 0.3 2:02.49 httpd 29089 apache 15 0 370m 48m 5188 S 1.0 0.3 2:27.61 httpd 29082 apache 15 0 390m 68m 5188 S 0.7 0.4 2:32.48 httpd 29984 apache 15 0 358m 36m 5228 S 0.7 0.2 2:08.32 httpd 3571 root 16 0 13400 1792 848 S 0.3 0.0 2:37.89 top 4419 mysql 15 0 668m 175m 7204 S 0.3 1.1 3:32.25 mysqld 28181 root 15 0 90460 3624 2680 S 0.3 0.0 0:17.60 sshd 29091 apache 15 0 390m 69m 5196 S 0.3 0.4 2:29.99 httpd 32476 root 15 0 12900 1320 848 R 0.3 0.0 0:06.46 top 1 root 15 0 10372 680 572 S 0.0 0.0 0:02.01 init 2 root RT -5 0 0 0 S 0.0 0.0 0:00.51 migration/0 3 root 34 19 0 0 0 S 0.0 0.0 0:00.07 ksoftirqd/0 4 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/0 5 root RT -5 0 0 0 S 0.0 0.0 0:00.12 migration/1 6 root 34 19 0 0 0 S 0.0 0.0 0:00.03 ksoftirqd/1 7 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/1 8 root RT -5 0 0 0 S 0.0 0.0 0:00.06 migration/2 9 root 34 19 0 0 0 S 0.0 0.0 0:00.03 ksoftirqd/2 10 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/2 11 root RT -5 0 0 0 S 0.0 0.0 0:00.06 migration/3 12 root 34 19 0 0 0 S 0.0 0.0 0:00.04 ksoftirqd/3 13 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/3 14 root RT -5 0 0 0 S 0.0 0.0 0:01.45 migration/4 15 root 34 19 0 0 0 S 0.0 0.0 0:00.01 ksoftirqd/4 16 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/4 17 root RT -5 0 0 0 S 0.0 0.0 0:00.22 migration/5 18 root 34 19 0 0 0 S 0.0 0.0 0:00.01 ksoftirqd/5 19 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/5 20 root RT -5 0 0 0 S 0.0 0.0 0:00.15 migration/6 21 root 34 19 0 0 0 S 0.0 0.0 0:00.02 ksoftirqd/6 22 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/6 23 root RT -5 0 0 0 S 0.0 0.0 0:00.15 migration/7 24 root 34 19 0 0 0 S 0.0 0.0 0:00.01 ksoftirqd/7 25 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/7 26 root RT -5 0 0 0 S 0.0 0.0 0:00.19 migration/8 27 root 34 19 0 0 0 S 0.0 0.0 0:00.04 ksoftirqd/8 28 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/8 29 root RT -5 0 0 0 S 0.0 0.0 0:00.34 migration/9 30 root 34 19 0 0 0 S 0.0 0.0 0:00.03 ksoftirqd/9 31 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/9 32 root RT -5 0 0 0 S 0.0 0.0 0:00.16 migration/10 33 root 34 19 0 0 0 S 0.0 0.0 0:00.04 ksoftirqd/10 34 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/10 35 root RT -5 0 0 0 S 0.0 0.0 0:00.12 migration/11 36 root 34 19 0 0 0 S 0.0 0.0 0:00.05 ksoftirqd/11 37 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/11 38 root RT -5 0 0 0 S 0.0 0.0 0:00.35 migration/12

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  • Why Is Vertical Resolution Monitor Resolution so Often a Multiple of 360?

    - by Jason Fitzpatrick
    Stare at a list of monitor resolutions long enough and you might notice a pattern: many of the vertical resolutions, especially those of gaming or multimedia displays, are multiples of 360 (720, 1080, 1440, etc.) But why exactly is this the case? Is it arbitrary or is there something more at work? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. The Question SuperUser reader Trojandestroy recently noticed something about his display interface and needs answers: YouTube recently added 1440p functionality, and for the first time I realized that all (most?) vertical resolutions are multiples of 360. Is this just because the smallest common resolution is 480×360, and it’s convenient to use multiples? (Not doubting that multiples are convenient.) And/or was that the first viewable/conveniently sized resolution, so hardware (TVs, monitors, etc) grew with 360 in mind? Taking it further, why not have a square resolution? Or something else unusual? (Assuming it’s usual enough that it’s viewable). Is it merely a pleasing-the-eye situation? So why have the display be a multiple of 360? The Answer SuperUser contributor User26129 offers us not just an answer as to why the numerical pattern exists but a history of screen design in the process: Alright, there are a couple of questions and a lot of factors here. Resolutions are a really interesting field of psychooptics meeting marketing. First of all, why are the vertical resolutions on youtube multiples of 360. This is of course just arbitrary, there is no real reason this is the case. The reason is that resolution here is not the limiting factor for Youtube videos – bandwidth is. Youtube has to re-encode every video that is uploaded a couple of times, and tries to use as little re-encoding formats/bitrates/resolutions as possible to cover all the different use cases. For low-res mobile devices they have 360×240, for higher res mobile there’s 480p, and for the computer crowd there is 360p for 2xISDN/multiuser landlines, 720p for DSL and 1080p for higher speed internet. For a while there were some other codecs than h.264, but these are slowly being phased out with h.264 having essentially ‘won’ the format war and all computers being outfitted with hardware codecs for this. Now, there is some interesting psychooptics going on as well. As I said: resolution isn’t everything. 720p with really strong compression can and will look worse than 240p at a very high bitrate. But on the other side of the spectrum: throwing more bits at a certain resolution doesn’t magically make it better beyond some point. There is an optimum here, which of course depends on both resolution and codec. In general: the optimal bitrate is actually proportional to the resolution. So the next question is: what kind of resolution steps make sense? Apparently, people need about a 2x increase in resolution to really see (and prefer) a marked difference. Anything less than that and many people will simply not bother with the higher bitrates, they’d rather use their bandwidth for other stuff. This has been researched quite a long time ago and is the big reason why we went from 720×576 (415kpix) to 1280×720 (922kpix), and then again from 1280×720 to 1920×1080 (2MP). Stuff in between is not a viable optimization target. And again, 1440P is about 3.7MP, another ~2x increase over HD. You will see a difference there. 4K is the next step after that. Next up is that magical number of 360 vertical pixels. Actually, the magic number is 120 or 128. All resolutions are some kind of multiple of 120 pixels nowadays, back in the day they used to be multiples of 128. This is something that just grew out of LCD panel industry. LCD panels use what are called line drivers, little chips that sit on the sides of your LCD screen that control how bright each subpixel is. Because historically, for reasons I don’t really know for sure, probably memory constraints, these multiple-of-128 or multiple-of-120 resolutions already existed, the industry standard line drivers became drivers with 360 line outputs (1 per subpixel). If you would tear down your 1920×1080 screen, I would be putting money on there being 16 line drivers on the top/bottom and 9 on one of the sides. Oh hey, that’s 16:9. Guess how obvious that resolution choice was back when 16:9 was ‘invented’. Then there’s the issue of aspect ratio. This is really a completely different field of psychology, but it boils down to: historically, people have believed and measured that we have a sort of wide-screen view of the world. Naturally, people believed that the most natural representation of data on a screen would be in a wide-screen view, and this is where the great anamorphic revolution of the ’60s came from when films were shot in ever wider aspect ratios. Since then, this kind of knowledge has been refined and mostly debunked. Yes, we do have a wide-angle view, but the area where we can actually see sharply – the center of our vision – is fairly round. Slightly elliptical and squashed, but not really more than about 4:3 or 3:2. So for detailed viewing, for instance for reading text on a screen, you can utilize most of your detail vision by employing an almost-square screen, a bit like the screens up to the mid-2000s. However, again this is not how marketing took it. Computers in ye olden days were used mostly for productivity and detailed work, but as they commoditized and as the computer as media consumption device evolved, people didn’t necessarily use their computer for work most of the time. They used it to watch media content: movies, television series and photos. And for that kind of viewing, you get the most ‘immersion factor’ if the screen fills as much of your vision (including your peripheral vision) as possible. Which means widescreen. But there’s more marketing still. When detail work was still an important factor, people cared about resolution. As many pixels as possible on the screen. SGI was selling almost-4K CRTs! The most optimal way to get the maximum amount of pixels out of a glass substrate is to cut it as square as possible. 1:1 or 4:3 screens have the most pixels per diagonal inch. But with displays becoming more consumery, inch-size became more important, not amount of pixels. And this is a completely different optimization target. To get the most diagonal inches out of a substrate, you want to make the screen as wide as possible. First we got 16:10, then 16:9 and there have been moderately successful panel manufacturers making 22:9 and 2:1 screens (like Philips). Even though pixel density and absolute resolution went down for a couple of years, inch-sizes went up and that’s what sold. Why buy a 19″ 1280×1024 when you can buy a 21″ 1366×768? Eh… I think that about covers all the major aspects here. There’s more of course; bandwidth limits of HDMI, DVI, DP and of course VGA played a role, and if you go back to the pre-2000s, graphics memory, in-computer bandwdith and simply the limits of commercially available RAMDACs played an important role. But for today’s considerations, this is about all you need to know. Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.     

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  • Parallel Classloading Revisited: Fully Concurrent Loading

    - by davidholmes
    Java 7 introduced support for parallel classloading. A description of that project and its goals can be found here: http://openjdk.java.net/groups/core-libs/ClassLoaderProposal.html The solution for parallel classloading was to add to each class loader a ConcurrentHashMap, referenced through a new field, parallelLockMap. This contains a mapping from class names to Objects to use as a classloading lock for that class name. This was then used in the following way: protected Class loadClass(String name, boolean resolve) throws ClassNotFoundException { synchronized (getClassLoadingLock(name)) { // First, check if the class has already been loaded Class c = findLoadedClass(name); if (c == null) { long t0 = System.nanoTime(); try { if (parent != null) { c = parent.loadClass(name, false); } else { c = findBootstrapClassOrNull(name); } } catch (ClassNotFoundException e) { // ClassNotFoundException thrown if class not found // from the non-null parent class loader } if (c == null) { // If still not found, then invoke findClass in order // to find the class. long t1 = System.nanoTime(); c = findClass(name); // this is the defining class loader; record the stats sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0); sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1); sun.misc.PerfCounter.getFindClasses().increment(); } } if (resolve) { resolveClass(c); } return c; } } Where getClassLoadingLock simply does: protected Object getClassLoadingLock(String className) { Object lock = this; if (parallelLockMap != null) { Object newLock = new Object(); lock = parallelLockMap.putIfAbsent(className, newLock); if (lock == null) { lock = newLock; } } return lock; } This approach is very inefficient in terms of the space used per map and the number of maps. First, there is a map per-classloader. As per the code above under normal delegation the current classloader creates and acquires a lock for the given class, checks if it is already loaded, then asks its parent to load it; the parent in turn creates another lock in its own map, checks if the class is already loaded and then delegates to its parent and so on till the boot loader is invoked for which there is no map and no lock. So even in the simplest of applications, you will have two maps (in the system and extensions loaders) for every class that has to be loaded transitively from the application's main class. If you knew before hand which loader would actually load the class the locking would only need to be performed in that loader. As it stands the locking is completely unnecessary for all classes loaded by the boot loader. Secondly, once loading has completed and findClass will return the class, the lock and the map entry is completely unnecessary. But as it stands, the lock objects and their associated entries are never removed from the map. It is worth understanding exactly what the locking is intended to achieve, as this will help us understand potential remedies to the above inefficiencies. Given this is the support for parallel classloading, the class loader itself is unlikely to need to guard against concurrent load attempts - and if that were not the case it is likely that the classloader would need a different means to protect itself rather than a lock per class. Ultimately when a class file is located and the class has to be loaded, defineClass is called which calls into the VM - the VM does not require any locking at the Java level and uses its own mutexes for guarding its internal data structures (such as the system dictionary). The classloader locking is primarily needed to address the following situation: if two threads attempt to load the same class, one will initiate the request through the appropriate loader and eventually cause defineClass to be invoked. Meanwhile the second attempt will block trying to acquire the lock. Once the class is loaded the first thread will release the lock, allowing the second to acquire it. The second thread then sees that the class has now been loaded and will return that class. Neither thread can tell which did the loading and they both continue successfully. Consider if no lock was acquired in the classloader. Both threads will eventually locate the file for the class, read in the bytecodes and call defineClass to actually load the class. In this case the first to call defineClass will succeed, while the second will encounter an exception due to an attempted redefinition of an existing class. It is solely for this error condition that the lock has to be used. (Note that parallel capable classloaders should not need to be doing old deadlock-avoidance tricks like doing a wait() on the lock object\!). There are a number of obvious things we can try to solve this problem and they basically take three forms: Remove the need for locking. This might be achieved by having a new version of defineClass which acts like defineClassIfNotPresent - simply returning an existing Class rather than triggering an exception. Increase the coarseness of locking to reduce the number of lock objects and/or maps. For example, using a single shared lockMap instead of a per-loader lockMap. Reduce the lifetime of lock objects so that entries are removed from the map when no longer needed (eg remove after loading, use weak references to the lock objects and cleanup the map periodically). There are pros and cons to each of these approaches. Unfortunately a significant "con" is that the API introduced in Java 7 to support parallel classloading has essentially mandated that these locks do in fact exist, and they are accessible to the application code (indirectly through the classloader if it exposes them - which a custom loader might do - and regardless they are accessible to custom classloaders). So while we can reason that we could do parallel classloading with no locking, we can not implement this without breaking the specification for parallel classloading that was put in place for Java 7. Similarly we might reason that we can remove a mapping (and the lock object) because the class is already loaded, but this would again violate the specification because it can be reasoned that the following assertion should hold true: Object lock1 = loader.getClassLoadingLock(name); loader.loadClass(name); Object lock2 = loader.getClassLoadingLock(name); assert lock1 == lock2; Without modifying the specification, or at least doing some creative wordsmithing on it, options 1 and 3 are precluded. Even then there are caveats, for example if findLoadedClass is not atomic with respect to defineClass, then you can have concurrent calls to findLoadedClass from different threads and that could be expensive (this is also an argument against moving findLoadedClass outside the locked region - it may speed up the common case where the class is already loaded, but the cost of re-executing after acquiring the lock could be prohibitive. Even option 2 might need some wordsmithing on the specification because the specification for getClassLoadingLock states "returns a dedicated object associated with the specified class name". The question is, what does "dedicated" mean here? Does it mean unique in the sense that the returned object is only associated with the given class in the current loader? Or can the object actually guard loading of multiple classes, possibly across different class loaders? So it seems that changing the specification will be inevitable if we wish to do something here. In which case lets go for something that more cleanly defines what we want to be doing: fully concurrent class-loading. Note: defineClassIfNotPresent is already implemented in the VM as find_or_define_class. It is only used if the AllowParallelDefineClass flag is set. This gives us an easy hook into existing VM mechanics. Proposal: Fully Concurrent ClassLoaders The proposal is that we expand on the notion of a parallel capable class loader and define a "fully concurrent parallel capable class loader" or fully concurrent loader, for short. A fully concurrent loader uses no synchronization in loadClass and the VM uses the "parallel define class" mechanism. For a fully concurrent loader getClassLoadingLock() can return null (or perhaps not - it doesn't matter as we won't use the result anyway). At present we have not made any changes to this method. All the parallel capable JDK classloaders become fully concurrent loaders. This doesn't require any code re-design as none of the mechanisms implemented rely on the per-name locking provided by the parallelLockMap. This seems to give us a path to remove all locking at the Java level during classloading, while retaining full compatibility with Java 7 parallel capable loaders. Fully concurrent loaders will still encounter the performance penalty associated with concurrent attempts to find and prepare a class's bytecode for definition by the VM. What this penalty is depends on the number of concurrent load attempts possible (a function of the number of threads and the application logic, and dependent on the number of processors), and the costs associated with finding and preparing the bytecodes. This obviously has to be measured across a range of applications. Preliminary webrevs: http://cr.openjdk.java.net/~dholmes/concurrent-loaders/webrev.hotspot/ http://cr.openjdk.java.net/~dholmes/concurrent-loaders/webrev.jdk/ Please direct all comments to the mailing list [email protected].

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  • Friday Fun: Fort Blaster – Ahoy There

    - by Asian Angel
    In this week’s game you and your pirate crew luck out and find a series of forts full of treasure waiting for you to claim in a campaign of high seas terror. So hoist the colors, grab your favorite cannon, and get ready to blast your way to fame and fortune! How to Banish Duplicate Photos with VisiPic How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It?

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