Subject: Re: Thread benchmarks, round 2
To: Kris Kennaway <>
From: Andrew Doran <>
List: tech-kern
Date: 10/05/2007 20:39:59
On Fri, Oct 05, 2007 at 09:08:07PM +0200, Kris Kennaway wrote:

> OK, I have repeated the benchmarking in two additional cases:
> 1) NetBSD with 8 CPUs and some kind of experimental kernel that Andrew 
> gave me (based on the vmlocking branch).  This is using the new scheduler.
> 2) As above with experimental libc and libpthread also given to me by 
> Andrew.  I dunno what changes these contain either :)

It's actually GENERIC.MP from current, with SCHED_M2. No vmlocking code
involved - would you be able to update the labels? The libc has jemalloc,
and libpthread is simply an up to date copy.
> I was only able to run in the 8 CPU configuration because when I tried 
> to disable CPUs with cpuctl, processes would hang under load.  This is 
> probably a scheduler issue.

Right, I doubt that bit has been well tested since the scheduler is so new.
> This shows some improvement but not much, relatively speaking.  In 
> particular performance at 4 threads is still significantly below FreeBSD 
> performance, which (given what I measured previously) suggests that 
> there is still a performance deficit with 4 CPUs on NetBSD.  It would be 
> nice to be able to test this directly though, maybe Andrew can give me a 
> kernel that has MAXCPU=4 or whatever the NetBSD version is.

Interesting. :-). Thanks for running this. I'm still optimistic about the 4
CPU case so I'm very interested in seeing what the results would be. I'll
have a look into the offline problem this evening.