On Mon, Jul 30, 2007 at 05:07:46PM -0400, Chris Snook wrote:
> [..] It's spending a lot less time in %sys despite the
> higher context switches, [..]
The workload takes 40% more so you've to add up that additional 40%
too into your math. "A lot less time" sounds an overstatement to
me. Also you'
Tim Chen wrote:
On Sat, 2007-07-28 at 02:51 -0400, Chris Snook wrote:
Tim --
Since you're already set up to do this benchmarking, would you mind
varying the parameters a bit and collecting vmstat data? If you want to
run oprofile too, that wouldn't hurt.
Here's the vmstat data. The nu
On Sat, 2007-07-28 at 02:51 -0400, Chris Snook wrote:
>
> Tim --
>
> Since you're already set up to do this benchmarking, would you mind
> varying the parameters a bit and collecting vmstat data? If you want to
> run oprofile too, that wouldn't hurt.
>
Here's the vmstat data. The num
On Fri, Jul 27, 2007 at 10:47:21PM -0400, Rik van Riel wrote:
> Tim Chen wrote:
> > Ingo,
> >
> > Volanomark slows by 80% with CFS scheduler on 2.6.23-rc1.
> > Benchmark was run on a 2 socket Core2 machine.
> >
> > The change in scheduler treatment of sched_yield
> > could play a part
> > Volanomark runs better
> > and is only 40% (instead of 80%) down from old scheduler
> > without CFS.
> 40 or 80 % is still a huge regression.
> Dmitry Adamushko
Can anyone explain precisely what Volanomark is doing? If it's something
dumb like "looping on sched_yield until the 'right' thread
On 28/07/07, Chris Snook <[EMAIL PROTECTED]> wrote:
> [ ... ]
> Under CFS, the yielding process will still be leftmost in the rbtree,
> otherwise it would have already been scheduled out.
Not actually true. The position of the 'current' task within the
rb-tree is updated with a timer tick's freq
On 28/07/07, Tim Chen <[EMAIL PROTECTED]> wrote:
> [ ... ]
> It may make sense to queue the
> yielding process a bit further behind in the queue.
> I made a slight change by zeroing out wait_runtime
> (i.e. have the process gives
> up cpu time due for it to run) for experimentation.
But that's wro
Andrea Arcangeli wrote:
On Fri, Jul 27, 2007 at 11:43:23PM -0400, Chris Snook wrote:
I'm pretty sure the point of posting a patch that triples CFS performance
on a certain benchmark and arguably improves the semantics of sched_yield
was to improve CFS. You have a point, but it is a point for a
On Fri, Jul 27, 2007 at 11:43:23PM -0400, Chris Snook wrote:
> I'm pretty sure the point of posting a patch that triples CFS performance
> on a certain benchmark and arguably improves the semantics of sched_yield
> was to improve CFS. You have a point, but it is a point for a different
> thread
Andrea Arcangeli wrote:
On Fri, Jul 27, 2007 at 08:31:19PM -0400, Chris Snook wrote:
I think Volanomark is being pretty stupid, and deserves to run slowly, but
Indeed, any app doing what volanomark does is pretty inefficient.
But this is not the point. I/O schedulers are pluggable to help for
Tim Chen wrote:
Ingo,
Volanomark slows by 80% with CFS scheduler on 2.6.23-rc1.
Benchmark was run on a 2 socket Core2 machine.
The change in scheduler treatment of sched_yield
could play a part in changing Volanomark behavior.
In CFS, sched_yield is implemented
by dequeueing and requeueing
On Fri, Jul 27, 2007 at 08:31:19PM -0400, Chris Snook wrote:
> I think Volanomark is being pretty stupid, and deserves to run slowly, but
Indeed, any app doing what volanomark does is pretty inefficient.
But this is not the point. I/O schedulers are pluggable to help for
inefficient apps too. If
Tim Chen wrote:
Ingo,
Volanomark slows by 80% with CFS scheduler on 2.6.23-rc1.
Benchmark was run on a 2 socket Core2 machine.
The change in scheduler treatment of sched_yield
could play a part in changing Volanomark behavior.
In CFS, sched_yield is implemented
by dequeueing and requeueing
Ingo,
Volanomark slows by 80% with CFS scheduler on 2.6.23-rc1.
Benchmark was run on a 2 socket Core2 machine.
The change in scheduler treatment of sched_yield
could play a part in changing Volanomark behavior.
In CFS, sched_yield is implemented
by dequeueing and requeueing a process . The ti
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