~100KB usleep() memory leak

~100KB usleep() memory leak

[Konstantin Ivlev]

[-- Attachment #1: Type: text/plain, Size: 1418 bytes --]

Hi All,

I have noticed ~100KB usleep() memory leak then compile mine
application under Cygwin. On Mac OS X 10.7 Lion it works fine (no
leak).
I am using Cygwin 1.7.11 version.
so, each call of usleep() I can see in Task Manager or Process
Explorer about ~100KB of memory are leaked. it is not so problematic,
but if I am using thread pool (e.g. 16 threads) it will leak about
~1MB per seconds, and several minutes of running application are
enough to waste all available memory ~4GB.

it is easy to reproduce. compile the following really simple source code :

#include <unistd.h>

int main()
{
	for (;;)
	{
		usleep(10);
	}
}

>g++ main.cpp

then run :

>./a.exe

and observe memory is leaking. to notice more huge memory leak,
compile the following simple example simulating thread pool :

#include <unistd.h>
#include <pthread.h>

void * ThreadProc(void *)
{
    for (;;)
	{
		usleep(10);
	}
	return NULL;
}

int main()
{
	size_t count = 16; // specify more to see bigger leak!
	pthread_t id;
	for (size_t i(0); i < count; ++i)
	pthread_create(&id, NULL, ThreadProc, NULL);
	for (;;);
	return NULL;
}

> g++ main.cpp

and run :

> ./a.exe

and observe huge and fast leaking memory. and if you comment usleep
call, memory leak will disapper.

I would be grateful if you could possibly advice something on this issue.

P.S. "cygcheck -s -v -r > cygcheck.out" execution log is in attachment
I am pleasant to enclose.

[-- Attachment #2: cygcheck.out --]
[-- Type: application/octet-stream, Size: 303803 bytes --]

[-- Attachment #3: sample1.cpp --]
[-- Type: text/x-c++src, Size: 73 bytes --]

#include <unistd.h>

int main()
{
	for (;;)
	{
		usleep(10);
	}
}

[-- Attachment #4: sample2.cpp --]
[-- Type: text/x-c++src, Size: 256 bytes --]

#include <unistd.h>
#include <pthread.h>

void * ThreadProc(void *)
{
    for (;;)
	{
		usleep(10);
	}
	return NULL;
}

int main()
{
	pthread_t id;
	for (size_t i(0); i < 16; ++i)
	pthread_create(&id, NULL, ThreadProc, NULL);
	for (;;);
}

[-- Attachment #5: Type: text/plain, Size: 218 bytes --]

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Re: ~100KB usleep() memory leak

[Corinna Vinschen]

On Mar 20 00:15, Konstantin Ivlev wrote:
> Hi All,
> 
> I have noticed ~100KB usleep() memory leak then compile mine
> application under Cygwin. On Mac OS X 10.7 Lion it works fine (no
> leak).
> I am using Cygwin 1.7.11 version.
> so, each call of usleep() I can see in Task Manager or Process
> Explorer about ~100KB of memory are leaked. it is not so problematic,
> but if I am using thread pool (e.g. 16 threads) it will leak about
> ~1MB per seconds, and several minutes of running application are
> enough to waste all available memory ~4GB.
> 
> it is easy to reproduce. compile the following really simple source code :
> 
> #include <unistd.h>
> 
> int main()
> {
> 	for (;;)
> 	{
> 		usleep(10);
> 	}
> }

Thanks for the report and the testcase.  I just applied a patch to fix
this memory leak.  I'm about tu generate a developer snapshot for
testing.  Please try the today's snapshot from http://cygwin.com/snapshots/
as soon as it is available.


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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Re: ~100KB usleep() memory leak

[marco atzeri]

On 3/19/2012 6:36 PM, Corinna Vinschen wrote:
> On Mar 20 00:15, Konstantin Ivlev wrote:
>> Hi All,
>>
>> I have noticed ~100KB usleep() memory leak then compile mine
>> application under Cygwin. On Mac OS X 10.7 Lion it works fine (no
>> leak).
>> I am using Cygwin 1.7.11 version.
>> so, each call of usleep() I can see in Task Manager or Process
>> Explorer about ~100KB of memory are leaked. it is not so problematic,
>> but if I am using thread pool (e.g. 16 threads) it will leak about
>> ~1MB per seconds, and several minutes of running application are
>> enough to waste all available memory ~4GB.
>>
>> it is easy to reproduce. compile the following really simple source code :
>>
>> #include<unistd.h>
>>
>> int main()
>> {
>> 	for (;;)
>> 	{
>> 		usleep(10);
>> 	}
>> }
>
> Thanks for the report and the testcase.  I just applied a patch to fix
> this memory leak.  I'm about tu generate a developer snapshot for
> testing.  Please try the today's snapshot from http://cygwin.com/snapshots/
> as soon as it is available.
>
>
> Thanks,
> Corinna
>

the new 20120319 snapshot seems to have collateral effect
on dash+rebaseall

     825 [waitproc] dash 3540! proc_waiter: error on read of child wait 
pipe 0x0,
  Win32 error 6


Marco

Marco


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Re: ~100KB usleep() memory leak

[Konstantin Ivlev]

thanks, I've tried cygwin1-20120319.dll.bz2 snapshot and can confirm memory leak 
has been completely fixed!

yours sincerely, Konstantin


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