Re: New lockless pagecache

From: Alok kataria
Date: Thu Sep 15 2005 - 14:52:47 EST


Hi Nick,

I have collected performance numbers for the lock less page cache
patch on the AIM - IO test.
The performance numbers are collected for 1-100 tasks 1-50 tasks and
90-100 tasks both for with and without your patch. This was done on
2.6.13 kernel.
There's definite improvement when the tasks are small i.e ~50-70. But
when the tasks go beyond 80, we see a large performance dip.
I again profiled the 90-100 runs with spinlock's inlined, but couldn't
understand the reason behind the performance difference.

Please find attached the performance numbers as well as the oprofile logs.

Thanks & Regards,
Alok


On 9/2/05, Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:
> Nick Piggin wrote:
>
> > I think this is getting pretty stable. No guarantees of course,
> > but it would be great if anyone gave it a test.
> >
>
> Or review, I might add. While I understand such a review is
> still quite difficult, this code really is far less complex
> than the previous lockless pagecache patches.
>
> (Ignore 1/7 though, which is a rollup - a broken out patchset
> can be provided on request)
>
> Nick
>
> --
> SUSE Labs, Novell Inc.
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--
A computer scientist is someone who, when told to "Go to Hell," sees
the "go to," rather than the destination, as harmful.

Alok Kataria

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