Date: Tue, 15 Aug 2006 20:22:19 +0200
From: Willy Tarreau <w@1wt.eu>
To: "linux-os (Dick Johnson)" <linux-os@analogic.com>
Cc: Irfan Habib <irfan.habib@gmail.com>,
       Linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: Maximum number of processes in Linux
Message-ID: <20060815182219.GL8776@1wt.eu>
References: <3420082f0608151059s40373a0bg4a1af3618c2b1a05@mail.gmail.com> <Pine.LNX.4.61.0608151419120.13947@chaos.analogic.com>
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On Tue, Aug 15, 2006 at 02:22:02PM -0400, linux-os (Dick Johnson) wrote:
> 
> On Tue, 15 Aug 2006, Irfan Habib wrote:
> 
> > Hi,
> >
> > What is the maximum number of process which can run simultaneously in
> > linux? I need to create an application which requires 40,000 threads.
> > I was testing with far fewer numbers than that, I was getting
> > exceptions in pthread_create
> >
> > Regards
> > Irfan
> 
> #include <stdio.h>
> int main(){
>      unsigned long i;
       ^^^^^^^^^^^^^^^^

>      while(fork() != -1)
>          i++;
>      printf("%u\n", i);
>      return 0;
> }
> $ gcc -o xxx xxx.c
> $ ./xxx
> 
> 1251392833         <<---- At least this number

Dick, would you please initialize your local variables when you send
examples like this ? You should have been amazed by one billion processes
on your box, at least.

> 1251392834
> 1251392834
> 1251392834
> 1251392834
> 1251392833
> 1251392833
> 1251392834
> 1251392834
> 1251392834
> ^C
> $ killall xxx
> 
> BYW 40,000 threads? 40,000 tasks all sharing the same address space?
> Hopefully this is just a training exercise to see if it's possible.
> 
> Cheers,
> Dick Johnson
> Penguin : Linux version 2.6.16.24 on an i686 machine (5592.62 BogoMips).
> New book: http://www.AbominableFirebug.com/

Regards,
Willy
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