Why is CompareAndSwap instruction considered expensive?
I read in a book:
"Memory barriers are expensive, about as
expensive as an atomic compareAndSet()
instruction."
Thanks!
I'm building a little script that will connect to an IMAP account and grab the content of the email and also the attachments. It works well for the most part, but when a really large file comes in, it causes the script to time out. Is there any way that I can check the file size before trying to grab it? I think that would be the simplest solution. Otherwise, I may have to upgrade to a server that has more memory.
Which CMS are you using in Java and what is your experience with it (in terms of extensibility, usage comfort, framework API, memory usage, performance etc.). I am looking for suggestions.
I was doing some work handling a lot of information and my partner told me that I was using too many matrices to manipulate the variables of the problem. The idea was to use one dimension arrays int a[] instead of the 2 dimensional arrays int b[][], to save memory and processing speed of the algorithm. How certain is that this change will accelerate the speed of execution or compilation of my code in c ++?
I have this code in base class
protected virtual bool HasAnyStuff<TObject>(TObject obj) where TObject:class
{
return false;
}
In child class I am overriding
protected override bool HasAnyStuff<Customer>(Customer obj)
{
//some stuff
if Customer.sth etc
return false;
}
I am getting this error
'''Type parameter declaration must be an identifier not a type'''
What is it I am doing wrong here?
Hi,
list<Dog*> dog;
.............
............
So I added many dog objects to it.
If I call dog.pop_front();
Does memory automatically gets deallocated ?
Does closing a java.sql.Connection also close all the statements, prepared statements, etc. obtained from that connection? Or is there going to be memory leak if I close the connection but leave the statements, etc. unclosed?
Hi,
I have a rdf file (file.trp) in n-triples format, where each line is:
"subject predicate object ."
I tried to use rdf_load in semweb/rdf_db to load it into memory, but failed. Here is what I tried:
?- rdf_load('file.trp').
?- rdf_load('file.trp', [format(triples]).
the manual says it supports xml and triples. But it only loads rdf xml files. How can I load such rdf triple file?
Thanks,
Li
$fp_src=fopen('file','r');
$filter = stream_filter_prepend($fp_src, 'convert.iconv.ISO-8859-1/UTF-8');
while(fread($fp_src,4096)){
++$count;
if($count%1000==0) print ftell($fp_src)."\n";
}
When I run this the script ends up consuming ~ 200 MB of RAM after going through just 35MB of the file.
Running it without the stream_filter zips right through with a constant memory footprint of ~10 MB.
What gives?
I have a class definition of the form
class X
{
public:
//class functions
private:
A_type *A;
//other class variables
};
and struct A_type is defined as
struct A_type
{
string s1,s2,s3;
};
Inside the constructor, I allocate appropriate memory for A and try A[0].s1="somestring";
It shows segmentation fault.
Is this kind of declaration invalid, or am I missing something
As I remember there is a magic command line option in Java that turn on writing of operations that are currently executed to console. The output was looked like byte code. I do not mean -verbose, because it prints only class loading, while this option outputs information like memory allocation etc.
Is there a more efficient way than using numpy.asarray() to generate an array from output in the form of a list?
This appears to be copying everything in memory, which doesn't seem like it would be that efficient with very large arrays.
(Updated) Example:
import numpy as np
a1 = np.array([1,2,3,4,5,6,7,8,9,10]) # pretend this has thousands of elements
a2 = np.array([3,7,8])
results = np.asarray([np.amax(np.where(a1 > element)) for element in a2])
If System.IO.Directory.Exists(HttpContext.Current.Server.MapPath(Server.MapPath("images/TravelogueGallery/" & getMaxID()))) Then
System.IO.Directory.Delete(HttpContext.Current.Server.MapPath("images/TravelogueGallery/" & getMaxID()), True)
End If
I am using the above code snippet to delete a directory but i get this error "'G:\Projects\Latest\LTCIndia 05-04-12 1415\images\TravelogueGallery\19' is not a valid virtual path. "
Whats wrong with the code?
I have some questions about singletons in C++.
Under what situations is a singleton a must?
What are the pros and cons of singletons? I was told they could cause memory leaks, how is that? I was also told that initialization is a problem, is that true?
I am sorting a hash in Perl. I encountered an Out of memory error when running my Perl Script:
foreach $key (sort (keys(%hash))) {
....
}
How do I sort a hash that has tons of data?
I have configured a Virtual Directory on IIS 6.0 running under UserA.
AppPool for the same is configured under Network Services.
I have one WCF svc file running under it,
My question is:
Is it running on UserA Account Or Network Service?
Is is bad practice to pass the Context to a constructor and save it as a private variable for internal use? The other option is to pass the Context as a parameter to methods that need it.
Which is the better option?
I have a feeling that passing to the constructor might result in memory leaks accidentally.
I have a C# application which sometimes cost the CPU very high. I want to see which part of the code cost most. But the Microsoft CLR Profiler only determins the memory usage, it's not meant for computational profiling according to here. Is there any tools to do this?
Thanks.
good day
we are developing game for android and have some trouble with resource loading on high dpi devices.
our resources are located in res/drawable directory
on a standart dpi device the game work properly, but on hdpi (tested on HTC Desire) all resources which located in res/drawable-hdpi load are loaded correctly, but the resources which miss in drawable-hdpi directory but present in res/drawable are ignored
but everything works fine on the virtual device with hdpi.
does anybody encounter this problem and know how to solve it?
If I have a Facebook app, and my users agree to allow my app to access their information, photos, friends, etc, is it ethical to grab their information when they log in, and then saving it in memory so that the next time he goes to my app, it can load faster?
If so, what about when the user logged off? Is the right thing to do to is to delete all the cached information and photos that the user provided?
Has Facebook got any way to detect that we're doing this (saving their information, etc)?
Hi,
I have a Virtual Machine with MOSS 2007 (Enterprise), VS2008 and SQL 2005.
I want to start exploring 2010. I need to know what I need to get started.
Can I donwload 2010 beta from Microsoft Site? Can I just install it without any conflicts with existing setup?
Thanks.
I was wondering how Java sorts items in the Map (HashMap or Hashtable) when they are added. Are the keys sorted by the hashcode, memory reference or by allocation precedence...?
It's because I've noticed same pairs in the Map are not always sorted in the same order
Hi, I have a structs action object instance that loads a variable from a properties file.I want it to happen only the first time the action is called, so in further executions its read from memory. Any hints ? Thanks.
I currently have a testing environment for web apps on a virtual machine.
The problem - i would like to keep IE 6 for testing and also have access to newer versions of IE as well.
How can i do this?
Thanks.