Re: ipc,sem: sysv semaphore scalability

From: Davidlohr Bueso
Date: Wed Mar 20 2013 - 16:57:10 EST

On Wed, 2013-03-20 at 13:49 -0700, Linus Torvalds wrote:
> On Wed, Mar 20, 2013 at 12:55 PM, Rik van Riel <riel@xxxxxxxxxxx> wrote:
> >
> > This series makes the sysv semaphore code more scalable,
> > by reducing the time the semaphore lock is held, and making
> > the locking more scalable for semaphore arrays with multiple
> > semaphores.
> The series looks sane to me, and I like how each individual step is
> pretty small and makes sense.
> It *would* be lovely to see this run with the actual Swingbench
> numbers. The microbenchmark always looked much nicer. Do the
> additional multi-semaphore scalability patches on top of Davidlohr's
> patches help with the swingbench issue, or are we still totally
> swamped by the ipc lock there?

Yes, I'm testing this patchset with my swingbench workloads. I should
have some numbers by today or tomorrow.

> Maybe there were already numbers for that, but the last swingbench
> numbers I can actually recall was from before the finer-grained
> locking..

Right, I couldn't get Oracle to run on the with the previous patches,
hopefully the bug(s) are now addressed.


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