Severe bug in GHC HEAD

[Simon Marlow]

On 09/02/11 22:54, Kyra wrote:
> Ghc HEAD has some severe bug. A have not filled an "official" bug report
> since I nave not isolated it properly. Below is how can I describe this
> bug:
>
> 1. Symptoms: under a heavy load *and* with RTS option -Nn where n > 1 my
> application stops responding to (http) requests. With -N1 all is ok.
> 2. Hardware: 4-core Intel CPU, OS: Windows 7 x64
> 3. ghc-7.1.20110201- are not affected, ghc-7.1.20110202+ are affected,
> stable ghcs are not affected too. So, the bug was introduced in a HEAD
> branch between Feb 1, 2011 and Feb 2, 2011.
> 4. If I increase "n" in -An RTS option my application proccesses more
> requests before choking. So one could guess the bug is GC-related.
>

Thanks for letting me know.  If you have a GHC build, can you try 
unpulling this patch

Wed Feb  2 03:49:07 PST 2011  Simon Marlow <marlowsd at gmail.com>
   * scheduleProcessInbox: use non-blocking acquire, and take the whole 
queue

and let me know if it helps?

Cheers,
	Simon