Messages in this thread |  | | | Date | Wed, 8 Nov 2006 17:22:02 +0100 | | From | Adrian Bunk <> | | Subject | Re: 2.6.19-rc5: known regressions |
On Wed, Nov 08, 2006 at 07:47:07AM -0800, Linus Torvalds wrote: > > > On Wed, 8 Nov 2006, Eric W. Biederman wrote: > > > > I haven't seen anyone reproduce this but Tim Chen, and Tim wasn't > > able to root cause the problem so I believe we are going to have > > this regression :( > > Note that you really shouldn't look too closely at lmbench scheduling > fluctuations. They can fluctuate a _lot_, especially under SMP, and it can > depend on things like cache layout that has nothing to do with the > scheduler (ie just code movement can make the lmbench numbers change). > > So there are "regressions" and there are "shit happens". It can sometimes > be hard to tell the two apart, of course ;)
There's perhaps one thing that might help us to see whether it's just a benchmark effekt or a real problem:
With Tim's CONFIG_NR_CPUS=8, NR_IRQS only increases from 224 in 2.6.18 to 512 in 2.6.19-rc.
With CONFIG_NR_CPUS=255, NR_IRQS increases from 224 in 2.6.18 to 8416 in 2.6.19-rc.
@Tim: Can you try CONFIG_NR_CPUS=255 with both 2.6.18 and 2.6.19-rc5?
> Linus
cu Adrian
--
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