From: Nick Piggin <npiggin@suse.de>
To: Chris Mason <chris.mason@oracle.com>,
Manfred Spraul <manfred@colorfullife.com>,
zach.brown@oracle.com, jens.axboe@oracle.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] ipc semaphores: reduce ipc_lock contention in semtimedop
Date: Wed, 14 Apr 2010 06:05:27 +1000 [thread overview]
Message-ID: <20100413200527.GG5683@laptop> (raw)
In-Reply-To: <20100413193801.GT13327@think>
On Tue, Apr 13, 2010 at 03:38:01PM -0400, Chris Mason wrote:
> On Wed, Apr 14, 2010 at 05:25:51AM +1000, Nick Piggin wrote:
> > I didn't notice anything that should make that go faster?
>
> Since I'm avoiding the ipc lock while operating on the array, it'll help
> any workload that hits on two or more semaphores in the array at
> once.
Yeah, I don't think SAP did that, significantly to matter. Possibly
some (aside from Oracle of course), do though.
> > Yes, with such a workload, using semops is basically legacy and simple
> > mutexes should work better. So I'm not outright against improving sysv
> > sem performance for more complex cases where nothing else we have works
> > as well.
> >
>
> I'm not in a hurry to overhaul a part of the kernel that has been stable
> for a long time. But it really needs some love I think. I'll have more
> numbers from a tpc run later this week.
Yep, I'm not against it. "industry standard benchmark" numbers would
be great.
I do think we need to be really careful with semantics though. The
API's been around for long enough that it is going to have been
(ab)used in every way possible :)
next prev parent reply other threads:[~2010-04-13 20:05 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-12 18:49 [PATCH RFC] Optimize semtimedop Chris Mason
2010-04-12 18:49 ` [PATCH 1/2] ipc semaphores: reduce ipc_lock contention in semtimedop Chris Mason
2010-04-13 17:15 ` Manfred Spraul
2010-04-13 17:39 ` Chris Mason
2010-04-13 18:09 ` Nick Piggin
2010-04-13 18:19 ` Chris Mason
2010-04-13 18:57 ` Nick Piggin
2010-04-13 19:01 ` Chris Mason
2010-04-13 19:25 ` Nick Piggin
2010-04-13 19:38 ` Chris Mason
2010-04-13 20:05 ` Nick Piggin [this message]
2010-05-16 16:57 ` Manfred Spraul
2010-05-16 22:40 ` Chris Mason
2010-05-17 7:20 ` Nick Piggin
2010-04-14 16:16 ` Manfred Spraul
2010-04-14 17:33 ` Chris Mason
2010-04-14 19:11 ` Manfred Spraul
2010-04-14 19:50 ` Chris Mason
2010-04-15 16:33 ` Manfred Spraul
2010-04-15 16:34 ` Chris Mason
2010-04-13 18:24 ` Zach Brown
2010-04-16 11:26 ` Manfred Spraul
2010-04-16 11:45 ` Chris Mason
2010-04-12 18:49 ` [PATCH 2/2] ipc semaphores: order wakeups based on waiter CPU Chris Mason
2010-04-17 10:24 ` Manfred Spraul
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