Search Results

Search found 10536 results on 422 pages for 'cpu usage'.

Page 374/422 | < Previous Page | 370 371 372 373 374 375 376 377 378 379 380 381  | Next Page >

• Regex to GENERATE thumbnails!?!?! (but that's crazy!)

  - by CryptoMonkey

  Hello everyone! So here is my situation, and the solution that I've come up with to solve the problem. I have created an application that includes TinyMCE to allow users to create HTML content for publishing. The user can include images in their markup, and drag/resize those images effecting the final Width/Height attributes in the IMG tag. This is all great, the users can include images and resize/relocate them to their desired appearance. But one big problem is that I am now sending a (possibly) much larger image to the client, only to have the browser resize the image into the requested Width/Height attributes. All that bandwidth and lost load time.... So my solution is to pre-process my users markup content, scanning all of the IMG tags and parsing out the Height/Width/Src attributes. Then set each img's SRC tag to a phpThumb request with the parsed Height/Width passed into the thumbnails URL. This will create my reduced size image (optimising bandwidth at the expense of CPU and caching). What do you think about this solution? I've seen other posts where people were using mod_rewrite to do something similar, but I want to effect the content on the page service and not manipulate the image requests as they're being received. .... Any thoughts about this design? I need some help with the fine details as my regex skills need some work, but I'm very short on time and promise to pay my technical knowledge debt soon. To make the regex's easier, I can be sure of some things. Only img tags that need this processing will have an existing width="" height="" attributes (with the double quotes, and lower cased text, but I suppose matching the text case insensitive would be better if TinyMCE changes) So a regex to match only the necessary Img tags, and maybe another three regex's to extract the src, the width, and the height? Thanks everyone.

  Read the article

• Aliasing `T*` with `char*` is allowed. Is it also allowed the other way around?

  - by StackedCrooked

  Note: This question has been renamed and reduced to make it more focused and readable. Most of the comments refer to the old text. According to the standard objects of different type may not share the same memory location. So this would not be legal: int i = 0; short * s = reinterpret_cast<short*>(&i); // BAD! The standard however allows an exception to this rule: any object may be accessed through a pointer to char or unsigned char: int i = 0; char * c = reinterpret_cast<char*>(&i); // OK However, it is not clear to me if this is also allowed the other way around. For example: char * c = read_socket(...); unsigned * u = reinterpret_cast<unsigned*>(c); // huh? Summary of the answers The answer is NO for two reasons: You an only access an existing object as char*. There is no object in my sample code, only a byte buffer. The pointer address may not have the right alignment for the target object. In that case dereferencing it would result in undefined behavior. On the Intel and AMD platforms it will result performance overhead. On ARM it will trigger a CPU trap and your program will be terminated! This is a simplified explanation. For more detailed information see answers by @Luc Danton, @Cheers and hth. - Alf and @David Rodríguez.

  Read the article

• Peculiar JRE behaviour running RMI server under load, should I worry?

  - by darri

  I've been developing a minimalistic Java rich client CRUD application framework for the past few years, mostly as a hobby but also actively using it to write applications for my current employer. The framework provides database access to clients either via a local JDBC based connection or a lightweight RMI server. Last night I started a load testing application, which ran 100 headless clients, bombarding the server with requests, each client waiting only 1 - 2 seconds between running simple use cases, consisting of selecting records along with associated detail records from a simple e-store database (Chinook). This morning when I looked at the telemetry results from the server profiling session I noticed something which to me seemed strange (and made me keep the setup running for the remainder of the day), I don't really know what conclusions to draw from it. Here are the results: Memory GC activity Threads CPU load Interesting, right? So the question is, is this normal or erratic? Is this simply the JRE (1.6.0_03 on Windows XP) doing it's thing (perhaps related to the JRE configuration) or is my framework design somehow causing this? Running the server against MySQL as opposed to an embedded H2 database does not affect the pattern. I am leaving out the details of my server design, but I'll be happy to elaborate if this behaviour is deemed erratic.

  Read the article

• Is the 'var' keyword bad? Or am I just old school?

  - by WaggingSiberian

  Recently I overheard junior developer ask "why do you use 'var' so much?". The mid-level developer responded "I use VAR all the time. I love it! I don't have to figure out the type." I didn't have the time or energy to get into a religious war and hey, I'm still the new guy here :-) I understand var has its place. LINQ comes to mind. But I have also always been told the use of var represents lazy programming and I should just use the correct type to begin with. If it's an int, define it as an int, not a var. When reviewing code, seeing the type makes it easier to follow. My opinion is, it's just lazy but there are exceptions. Var also reminds me of the VB/VBA variant type. It also had its place. I recall (from many years ago) its usage being less-than-desirable type and it was rather resource hungry. Am I just being stuck in my ways? Should we start using var all the time as my co-worker does?

  Read the article

• How do I slow down a flash game?

  - by dsaccount1

  Basically the objective is to click on certain targets, which upon doing so would destroy the target and garner you points. I've written a macro to help me until the point where its impossible to even see the target more than a mere flicker, (maybe even less than that, i cant see it with my eyes). But its possible because i believe others have done so. (Maybe on slower comps?) Anyway the question is, how would it be possible to slow down the flash game? I've thought of a couple of ways that could work but i'm not sure how to implement them. 1. Slow down the cpu speed? (smth like that? how?) 2. As the game progress the time the targets appear and stay up is reduced. Maybe theres a variable controlling all of this, isit possible to modify the address of this variable? freeze it or smth? Any ideas, suggestions and especially advice would really be appreciated, thanks!

  Read the article

• WINDOWS: Your computer hangs. You can windows + R (run dialog) but performance is so halted taskMGR

  - by John Sullivan

  The question is, what process are available to try to recover from total system instability before pulling the plug when we can do nothing but programs or batches in the path from the run dialog (windows + r key), and performance is so dead that taskMGR / procEXP / other programs with visual guis are not usable? I am not a windows expert, but ideally someone out there has written a program that does more or less stuff like this: Immediately set (or perhaps I can set from the run prompt) its priority to extremely high, evaluate performance bottlenecks. E.g. is CPU 100%? If so identify offending program(s) or problems. Attempt / log fixes, then provide crude feedback asking the user if his performance has stabilized enough to abort, wait a few seconds, if no feedback continue, etc. etc. Eventually try to do any "system cleanup" if the program decides it cannot recover and perhaps finally provide a series of beeps to the user, or what have you, to say "OK, I give up, time to pull the plug". Ideally create a log, when able. These kinds of horrible hangs are a situation where surely trying something, anything, is better than nothing -- as long as that something is intelligent -- when the alternative is ripping out the power coord. Again, I am not a windows expert, so perhaps there is a much more elegant "hands on" approach I am not aware of.

  Read the article

• C Population Count of unsigned 64-bit integer with a maximum value of 15

  - by BitTwiddler1011

  I use a population count (hamming weight) function intensively in a windows c application and have to optimize it as much as possible in order to boost performance. More than half the cases where I use the function I only need to know the value to a maximum of 15. The software will run on a wide range of processors, both old and new. I already make use of the POPCNT instruction when Intel's SSE4.2 or AMD's SSE4a is present, but would like to optimize the software implementation (used as a fall back if no SSE4 is present) as much as possible. Currently I have the following software implementation of the function: inline int population_count64(unsigned __int64 w) { w -= (w 1) & 0x5555555555555555ULL; w = (w & 0x3333333333333333ULL) + ((w 2) & 0x3333333333333333ULL); w = (w + (w 4)) & 0x0f0f0f0f0f0f0f0fULL; return int(w * 0x0101010101010101ULL) 56; } So to summarize: (1) I would like to know if it is possible to optimize this for the case when I only want to know the value to a maximum of 15. (2) Is there a faster software implementation (for both Intel and AMD CPU's) than the function above?

  Read the article

• Extensions methods and forward compatibilty of source code.

  - by TcKs

  Hi, I would like solve the problem (now hypothetical but propably real in future) of using extension methods and maginification of class interface in future development. Example: /* the code written in 17. March 2010 */ public class MySpecialList : IList<MySpecialClass> { // ... implementation } // ... somewhere elsewhere ... MySpecialList list = GetMySpecialList(); // returns list of special classes var reversedList = list.Reverse().ToList(); // .Reverse() is extension method /* now the "list" is unchanged and "reveresedList" has same items in reversed order */ /* --- in future the interface of MySpecialList will be changed because of reason XYZ*/ /* the code written in some future */ public class MySpecialList : IList<MySpecialClass> { // ... implementation public MySpecialList Reverse() { // reverse order of items in this collection return this; } } // ... somewhere elsewhere ... MySpecialList list = GetMySpecialList(); // returns list of special classes var reversedList = list.Reverse().ToList(); // .Reverse() was extension method but now is instance method and do something else ! /* now the "list" is reversed order of items and "reveresedList" has same items lake in "list" */ My question is: Is there some way how to prevent this case (I didn't find them)? If is now way how to prevent it, is there some way how to find possible issues like this? If is now way how to find possible issues, should I forbid usage of extension methods? Thanks.

  Read the article

• IS operator behaving a bit strangely

  - by flockofcode

  1) According to my book, IS operator can check whether expression E (E is type) can be converted to the target type only if E is either a reference conversion, boxing or unboxing. Since in the following example IS doesn’t check for either of the three types of conversion, the code shouldn’t work, but it does: int i=100; if (i is long) //returns true, indicating that conversion is possible l = i; 2) a) B b; A a = new A(); if (a is B) b = (B)a; int i = b.l; class A { public int l = 100; } class B:A { } The above code always causes compile time error “Use of unassigned variable”. If condition a is B evaluates to false, then b won’t be assigned a value, but if condition is true, then it will. And thus by allowing such a code compiler would have no way of knowing whether the usage of b in code following the if statement is valid or not ( due to not knowing whether a is b evaluates to true or false) , but why should it know that? Intsead why couldn’t runtime handle this? b) But if instead we’re dealing with non reference types, then compiler doesn’t complain, even though the code is identical.Why? int i = 100; long l; if (i is long) l = i; thank you

  Read the article

• Are programming languages and methods ineffective? (assembler and C knowledge needed)

  - by b-gen-jack-o-neill

  Hi, for a long time, I am thinking and studying output of C language compiler in asemlber form, as well as CPU architecture. I know this may be silly to you, but it seems to me that something is very ineffective. Please, don´t be angry if I am wrong, and there is some reason I do not see for all these principles. I will be very glad if you tell me why is it designed this way. I actually trully believe I am wrong, I know the genius minds of people which get PCs together knew a reason to do so. What exactly, do you ask? I´ll tell you right away, I use C as a example: 1, Stack local scope memory allocation: So, typical local memory allocation uses stack. Just copy esp to ebp and than allocate all the memory via ebp. OK, I would understand this if you explicitly need allocate RAM by default stack values, but if I do understand it correctly, modern OS use paging as a translation layer between application and physical RAM, when adress you desire is further translated before reaching actuall RAM byte. So why don´t just say 0x00000000 is int a,0x00000004 is int b and so? And access them just by mov 0x00000000,#10? Becouse you wont actually access memory blocks 0x00000000 and 0x00000004 but those your OS set the paging tables to. Actually, since memory allocation by ebp and esp use indirect adressing, "my" way would be even faster. 2, Variable allocation duplicitly: When you run aaplication, Loader load its code into RAM. When you create variable, or string, compiler generates code that pushes these values on the top o stack when created in main. So there is actuall instruction for do so, and that actuall number in memory. So, there are 2 entries of the same value in RAM. One in fomr of instruction, second in form of actuall bytes in the RAM. But why? Why not to just when declaring variable count at which memory block it would be, than when used, just insert this memory location?

  Read the article

• Why is the 'var' keyword bad? Or am I just old school?

  - by WaggingSiberian

  Recently I overheard junior developer ask "why do you use 'var' so much?". The mid-level developer responded "I use VAR all the time. I love it! I don't have to figure out the type." I didn't have the time or energy to get into a religious war and hey, I'm still the new guy here :-) I understand var has its place. LINQ comes to mind. But I have also always been told the use of var represents lazy programming and I should just use the correct type to begin with. If it's an int, define it as an int, not a var. When reviewing code, seeing the type makes it easier to follow. My opinion is, it's just lazy but there are exception. Var also reminds me of the VB/VBA variant type. It also had its place. I recall (from many years ago) its usage being less-than-desirable type and it was rather resource hungry. Am I just being stuck in my ways? Should we start using var all the time as my co-worker does?

  Read the article

• App Crashing Inspite of Being ARC Enabled

  - by proctr

  I have been working on an iOS App for sometime now and its almost ready to submit. However, when I gave it to few people for testing purposes (running iOS 5)..they reported cases where the app crashes and the home screen is displayed on the phone OR a frozen app screen appears with no response whatsoever The app is ARC enabled and Xcode shows no warnings. So, I'm relli tensed about what's going wrong. I have declared properties in the following fashion: @property (nonatomic) IBOutlet UILabel *devCountLabel; @property (nonatomic) IBOutlet UIView *splashView; Likewise other properties are declared. Could anyone provide a solution ASAP. It is mainly a network based app and thus, CoreData usage is minimum.. Anyway, I'm running out of time..So Please provide a fix asap..oh and thanks a ton for it. PS: The App doesn't crash in the simulator, so I'm guessing it has something related to memory. And the crashes are random. So, repeating a set of steps to reproduce the crash doesn't help either. For Eg. When I click a button, modalViewControllerAnimation results in normal case. Now this occurs as expected most of the time and freezes the app other times.

  Read the article

• How to optimize this simple function which translates input bits into words?

  - by psihodelia

  I have written a function which reads an input buffer of bytes and produces an output buffer of words where every word can be either 0x0081 for each ON bit of the input buffer or 0x007F for each OFF bit. The length of the input buffer is given. Both arrays have enough physical place. I also have about 2Kbyte free RAM which I can use for lookup tables or so. Now, I found that this function is my bottleneck in a real time application. It will be called very frequently. Can you please suggest a way how to optimize this function? I see one possibility could be to use only one buffer and do in-place substitution. void inline BitsToWords(int8 *pc_BufIn, int16 *pw_BufOut, int32 BufInLen) { int32 i,j,z=0; for(i=0; i<BufInLen; i++) { for(j=0; j<8; j++, z++) { pw_BufOut[z] = ( ((pc_BufIn[i] >> (7-j))&0x01) == 1? 0x0081: 0x007f ); } } } Please do not offer any compiler specific or CPU/Hardware specific optimization, because it is a multi-platform project.

  Read the article

• A basic load test question

  - by user236131

  I have a very basic load test question. I am running a load test using VSTS 2008 and I have test rig with controller + 10 agents. This load test is against a SharePoint farm I have. My goal of the load test is to find out the resource utilization on web+app+db tiers of my farm for any given load scenario. An example of a load scenario is Usage profile: Average collaboration (as defined by SCCP) User Load: 500 (using step load pattern=a step of 50 every 2 mins and a warm up time of 2mins for every step) Think time: 0 Load duration: 8hrs Now, the question is: Is it fair to expect that metrics like Requests/sec, %processor time on web front end / App / DB, Test/sec, and etc become flat or enter a steady state at one point in time during the load test. Like I said, the goal is not to create a bottleneck but to only measure the utilization of resources by the above load profile. I am asking this question because I see something different. At one point in the load test, requests/sec becomes more or less flat. But processor utilization on the web/DB servers keeps increasing. After digging through the data a bit, I see that "tests running" counter also steadily increased over time. So, if I run the load test for more than 8hrs, %processor may go up further. This way, I don't know what to consider as the load excreted by the load profile. What does this "tests running" counter really signify? How is this different from tests/sec? Another question is: how can I find out why "tests running" counter shows an increase overtime? Thanks for your time

  Read the article

• PHP shell_exec() - Run directly, or perform a cron (bash/php) and include MySQL layer?

  - by Jimbo

  Sorry if the title is vague - I wasn't quite sure how to word it! What I'm Doing I'm running a Linux command to output data into a variable, parse the data, and output it as an array. Array values will be displayed on a page using PHP, and this PHP page output is requested via AJAX every 10 seconds so, in effect, the data will be retrieved and displayed/updated every 10 seconds. There could be as many as 10,000 characters being parsed on every request, although this is usually much lower. Alternative Idea I want to know if there is a better* alternative method of retrieving this data every 10 seconds, as multiple users (<10) will be having this command executed automatically for them. A cronjob running on the server could execute either bash or php (which is faster?) to grab the data and store it in a MySQL database. Then, any AJAX calls to the PHP output would return values in the MySQL database rather than making a direct call to execute server code every 10 seconds. Why? I know there are security concerns with running execs directly from PHP, and (I hope this isn't micro-optimisation) I'm worried about CPU usage on the server. The server is running a sempron processor. Yes, they do still exist. Having this only execute when the user is on the page (idea #1) means that the server isn't running code that doesn't need to be run. However, is this slow and insecure? Just in case the type of linux command may be of assistance in determining it's efficiency: shell_exec("transmission-remote $host:$port --auth $username:$password -l"); I'm hoping that there are differences in efficiency and level of security with the two methods I have outlined above, and that this isn't just micro-micro-optimisation. If there are alternative methods that are better*, I'd love to learn about these! :)

  Read the article

• Optimize Duplicate Detection

  - by Dave Jarvis

  Background This is an optimization problem. Oracle Forms XML files have elements such as: <Trigger TriggerName="name" TriggerText="SELECT * FROM DUAL" ... /> Where the TriggerText is arbitrary SQL code. Each SQL statement has been extracted into uniquely named files such as: sql/module=DIAL_ACCESS+trigger=KEY-LISTVAL+filename=d_access.fmb.sql sql/module=REP_PAT_SEEN+trigger=KEY-LISTVAL+filename=rep_pat_seen.fmb.sql I wrote a script to generate a list of exact duplicates using a brute force approach. Problem There are 37,497 files to compare against each other; it takes 8 minutes to compare one file against all the others. Logically, if A = B and A = C, then there is no need to check if B = C. So the problem is: how do you eliminate the redundant comparisons? The script will complete in approximately 208 days. Script Source Code The comparison script is as follows: #!/bin/bash echo Loading directory ... for i in $(find sql/ -type f -name \*.sql); do echo Comparing $i ... for j in $(find sql/ -type f -name \*.sql); do if [ "$i" = "$j" ]; then continue; fi # Case insensitive compare, ignore spaces diff -IEbwBaq $i $j > /dev/null # 0 = no difference (i.e., duplicate code) if [ $? = 0 ]; then echo $i :: $j >> clones.txt fi done done Question How would you optimize the script so that checking for cloned code is a few orders of magnitude faster? System Constraints Using a quad-core CPU with an SSD; trying to avoid using cloud services if possible. The system is a Windows-based machine with Cygwin installed -- algorithms or solutions in other languages are welcome. Thank you!

  Read the article

• How security of the systems might be improved using database procedures?

  - by Centurion

  The usage of Oracle PL/SQL procedures for controlling access to data often emphasized in PL/SQL books and other sources as being more secure approach. I'v seen several systems where all business logic related with data is performed through packages, procedures and functions, so application code becomes quite "dumb" and is only responsible for visualization part. I even heard some devs call such approaches and driving architects as database nazi :) because all logic code resides in database. I do know about DB procedure performance benefits, but now I'm interested in a "better security" when using thick client model. I assume such design mostly used when Oracle (and maybe MS SQL Server) databases are used. I do agree such approach improves security but only if there are not much users and every system user has a database account, so we might control and monitor data access through standard database user security. However, how such approach could increase the security for an average web system where thick clients are used: for example one database user with DML grants on all tables, and other users are handled using "users" and"user_rights" tables? We could use DB procedures, save usernames into context use that for filtering but vulnerability resides at the root - if the main database account is compromised than nothing will help. Of course in a real system we might consider at least several main users (for example frontend_db_user, backend_db_user).

  Read the article

• Setting up a NAS with Citrix XenServer

  - by JasonBrown

  Just a quick query on anyone whos worked with XenServer, I want to setup a NAS at home but with virtualization (I've looked into VMWare Server and KVM, I quite like KVM!) but I was told about XenServer 5.5. I have comomodity hardware (ASUS board, dual core 2.66Ghz CPU with 8Gb RAM), I need to setup a fileserver to house about 2-3Tb worth of data (big chunky video - not porn!). Need to run Linux (preferably CentOS) but also run Windows virtualised for testing. I was thinking of going the XenServer route, however I want to be able to offer a VM access to the 2-3Tb of HDDs (5 HDD drives) directly so it can do its thing (maybe using FreeNAS). Would this be possible with XenServer? Or will I have to do more work - and another box - to offer this? My goals are to use FreeNAS (ZFS!) for the filesserver, CentOS for SVN and aother bits we need to use (LAMP Stack), Windows for our win32 testing all on one box. I see this iSCSI target bits and get scared.

  Read the article

• C# properties: How are they instantiated?

  - by Pedery

  Hi! This might be a pretty straightforward question, but I'm trying to understand some of the internal workings of the compilation. Very simply put, imagine an arbitrary object being instantiated. This object is then allocated on the heap. The object has a property of type PointF (which is value type), with a get and a set method. Imagine the get and the set method containing a few calculations for doing their work. How and where (stack/heap) and when is this code instantiated? This is the background for this question: I'm writing get and set methods for an object and these methods need to be accessed very frequently. The get and set code in itself is rather massive so I feared that in a worst case scenario the methods would be instantiated as an object or a value type with all internal code for every access of the property. On the other hand the code is probably instantiated when the main object is created and the CPU is simply told to jmp to the property code start. Anyway, this is what I want to have clarified.

  Read the article

• Memory increases with Java UDP Server

  - by Trevor

  I have a simple UDP server that creates a new thread for processing incoming data. While testing it by sending about 100 packets/second I notice that it's memory usage continues to increase. Is there any leak evident from my code below? Here is the code for the server. public class UDPServer { public static void main(String[] args) { UDPServer server = new UDPServer(15001); server.start(); } private int port; public UDPServer(int port) { this.port = port; } public void start() { try { DatagramSocket ss = new DatagramSocket(this.port); while(true) { byte[] data = new byte[1412]; DatagramPacket receivePacket = new DatagramPacket(data, data.length); ss.receive(receivePacket); new DataHandler(receivePacket.getData()).start(); } } catch (IOException e) { e.printStackTrace(); } } } Here is the code for the new thread that processes the data. For now, the run() method doesn't do anything. public class DataHandler extends Thread { private byte[] data; public DataHandler(byte[] data) { this.data = data; } @Override public void run() { System.out.println("run"); } }

  Read the article

• Python, web log data mining for frequent patterns

  - by descent

  Hello! I need to develop a tool for web log data mining. Having many sequences of urls, requested in a particular user session (retrieved from web-application logs), I need to figure out the patterns of usage and groups (clusters) of users of the website. I am new to Data Mining, and now examining Google a lot. Found some useful info, i.e. querying Frequent Pattern Mining in Web Log Data seems to point to almost exactly similar studies. So my questions are: Are there any python-based tools that do what I need or at least smth similar? Can Orange toolkit be of any help? Can reading the book Programming Collective Intelligence be of any help? What to Google for, what to read, which relatively simple algorithms to use best? I am very limited in time (to around a week), so any help would be extremely precious. What I need is to point me into the right direction and the advice of how to accomplish the task in the shortest time. Thanks in advance!

  Read the article

• Prototype or jQuery for DOM manipulation (client-side dynamic content)

  - by luiggitama

  I need to know which of these two JavaScript frameworks is better for client-side dynamic content modification for known DOM elements (by id), in terms of performance, memory usage, etc.: Prototype's $('id').update(content) jQuery's jQuery('#id').html(content) BTW, both libraries coexist with no conflict in my app, because I'm using RichFaces for JSF development, that's why I can use "jQuery" instead of "$". I have at least 20 updatable areas in my page, and for each one I prepare content (tables, option lists, etc.), based on some user-defined client-side criteria filtering or some AJAX event, etc., like this: var html = []; int idx = 0; ... html[idx++] = '<tr><td class="cell"><span class="link" title="View" onclick="myFunction('; html[idx++] = param; html[idx++] = ')"></span>'; html[idx++] = someText; html[idx++] = '</td></tr>'; ... So here comes the question, which is better to use: // Prototype's $('myId').update(html.join('')); // or jQuery's jQuery('#myId').html(html.join('')); Other needed functions are hide() and show(), which are present in both frameworks. Which is better? Also I'm needing to enable/disable form controls, and to read/set their values. Note that I know my updatable area's id (I don't need CSS selectors at this point). And I must tell that I'm saving these queried objects in some data structure for later use, so they are requested just once when the page is rendered, like this: MyData = {div1:jQuery('#id1'), div2:$('id2'), ...}; ... div1.update('content 1'); div2.html('content 2'); So, which is the best practice?

  Read the article

• In sync query calls, one query causing other query to run slower. Why?

  - by Irchi

  Sorry for the long question, but I think this is an interesting situation and I couldn't find any explanations for it: I was involved in optimization of an application that performed a large number of sequential SELECT and INSERT statements on a single dedicated SQL Server database. The process needs to INSERT a large number of records into a table, but for each of them there should be some value mappings, which performed using SELECT statements on another table in the same database. For a specific execution, it took 90 minutes to run. I used a profiler (JProfiler - the application is Java-based) to determine how much time does each part of the application take. It yields that 60% of the time was spent on INSERT method calls, and almost 20% on SELECT calls (the rest distributed in other parts). After some trials, I came to this situation: I commented out the INSERT query that took 60% of the time. I was expecting for the total run time to be around 35 minutes, as I have removed 60% of the 90 minutes. But the whole process took the same 90 minutes (doing only SELECTs and nothing else), but each SELECT took longer this time! Everything was running sync, there were no async calls. And there was only one single thread of execution. SELECT and INSERT queries are very simple, and don't have anything special, and they are on different tables, but on the same DB. I tested with both the DB on the application machine, and on a remote network machine. I can't think of any explanation for this, as the Profiler (Application profiler, not SQL Profiler) reported the changes in the method call times, and by removing INSERT statements SELECT statements took longer to run. Can anyone give me some kind of explanation of what could have happened? (there can't be cache / query optimization stuff, because the queries were run in sync, and in a single thread, and it was far from affecting the cache this much) I should note that the bottleneck of the speed was in SQL server, using most of the CPU time.

  Read the article

• Setting pixel values in Nvidia NPP ImageCPU objects?

  - by solvingPuzzles

  In the Nvidia Performance Primitives (NPP) image processing examples in the CUDA SDK distribution, images are typically stored on the CPU as ImageCPU objects, and images are stored on the GPU as ImageNPP objects. boxFilterNPP.cpp is an example from the CUDA SDK that uses these ImageCPU and ImageNPP objects. When using a filter (convolution) function like nppiFilter, it makes sense to define a filter as an ImageCPU object. However, I see no clear way setting the values of an ImageCPU object. npp::ImageCPU_32f_C1 hostKernel(3,3); //allocate space for 3x3 convolution kernel //want to set hostKernel to [-1 0 1; -1 0 1; -1 0 1] hostKernel[0][0] = -1; //this doesn't compile hostKernel(0,0) = -1; //this doesn't compile hostKernel.at(0,0) = -1; //this doesn't compile How can I manually put values into an ImageCPU object? Notes: I didn't actually use nppiFilter in the code snippet; I'm just mentioning nppiFilter as a motivating example for writing values into an ImageCPU object. The boxFilterNPP.cpp example doesn't involve writing directly to an ImageCPU object, because nppiFilterBox is a special case of nppiFilter that uses a built-in gaussian smoothing filter (probably something like [1 1 1; 1 1 1; 1 1 1]).

  Read the article

• Image resizing efficiency in C# and .NET 3.5

  - by Matthew Nichols

  I have written a web service to resize user uploaded images and all works correctly from a functional point of view, but it causes CPU usage to spike every time it is used. It is running on Windows Server 2008 64 bit. I have tried compiling to 32 and 64 bit and get about the same results. The heart of the service is this function: private Image CreateReducedImage(Image imgOrig, Size NewSize) { var newBM = new Bitmap(NewSize.Width, NewSize.Height); using (var newGrapics = Graphics.FromImage(newBM)) { newGrapics.CompositingQuality = CompositingQuality.HighSpeed; newGrapics.SmoothingMode = SmoothingMode.HighSpeed; newGrapics.InterpolationMode = InterpolationMode.HighQualityBicubic; newGrapics.DrawImage(imgOrig, new Rectangle(0, 0, NewSize.Width, NewSize.Height)); } return newBM; } I put a profiler on the service and it seemed to indicate the vast majority of the time is spent in the GDI+ library itself and there is not much to be gained in my code. Questions: Am I doing something glaringly inefficient in my code here? It seems to conform to the example I have seen. Are there gains to be had in using libraries other than GDI+? The benchmarks I have seen seem to indicate that GDI+ does well compare to other libraries but I didn't find enough of these to be confident. Are there gains to be had by using "unsafe code" blocks? Please let me know if I have not included enough of the code...I am happy to put as much up as requested but don't want to be obnoxious in the post.

  Read the article

< Previous Page | 370 371 372 373 374 375 376 377 378 379 380 381  | Next Page >