Subject: Re: sa/pthread smp concurrency (includes patch)
To: Christian Limpach <>
From: Bill Studenmund <>
List: tech-kern
Date: 07/14/2003 08:12:16
On Fri, 11 Jul 2003, Christian Limpach wrote:

> Hello!
> I have made the necessary changes to allow a threaded application to use
> multiple CPUs if available.  So far this was not possible because an
> SA-application could only have one active thread.  Now top shows that my
> simple test program which creates several cpu-hungry threads uses close to
> 200% on my otherwise idle two-cpu machine.  transcode used to encode at
> 3fps, it's now encoding at almost 5fps (before it crashes :-().
> The patch adds concurrency support.  It also adds support for cpu-affinity-
> masks (options MPCPUMASK in your kernel config file) which is used to
> address the SMP-specific SA-problems (LWPs fighting over the VP).  Finally
> it includes large parts from Stephan Uphoff's patch to address the
> signal/memory problems.  It's missing locking of the SA data structures
> within the kernel and this will occasionally terminate an application or
> even panic.

Could you please break this up into smaller pieces? Your work and
Stephan's has done a lot of bug fixing, and you're adding (important)
features. Please separate the two, and check in the bug fixes soon. :-) I
think things like cpu-affinity will need some discussions before we go
with them (for instance, how would a bit-maks work on a system with 16 or
512 nodes?). I personally would prefer that pthread bug fixes don't have
to wait for that discussion to conclude. ;-)

Take care,