Re: spawning (exec*/wait) shows non-constant time if memory grows

[OndÅej BÃlka <neleai at seznam dot cz>]

On Fri, Jan 24, 2014 at 05:04:14PM +0530, Siddhesh Poyarekar wrote:
> On 23 January 2014 23:50, Dirk Bächle <tshortik@gmx.de> wrote:
> > Hi there,
> >
> > I've already posted my actual question to the kernel-dev mailing list at:
> >
> >   https://lkml.org/lkml/2014/1/14/632
> 
> The link seems to be broken.  It just shows a blank LKML template page.
>
It works for me, try again.
 
> > , but got no reaction so far. So I'd really appreciate if someone
> > knowledgeable could have a look at my findings and confirm to me that the
> > problem I see is a kernel issue...and not related to the glibc itself.
> > What it's basically about is: I spawn a large number of simple child
> > processes sequentially (they don't run in parallel!) while letting the
> > memory of the parent process go up with malloc(). Over the number of spawned
> > processes the runtime for each execve/wait seems to grow, which is not what
> > I would expect.
> 
> If the memory footprint of the parent process increases, the time
> taken to clone it will increase as well since it has to clone the
> parent address space.  We don't have a light-weight exec* syscall
> similar to the Windows CreateProcess() functionality yet, where one
> would not bother cloning the parent address space only to throw it
> away in an exec.  I believe there were discussions about it in the
> past on the libc-alpha mailing list.
> 
> Siddhesh
> -- 
> http://siddhesh.in

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