From: Manfred Spraul <manfred@colorfullife.com>
To: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
hhuang@redhat.com, Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 0/4] ipc/sem.c: Bug fixes, regression fixes, v3
Date: Mon, 27 May 2013 17:57:11 +0200 [thread overview]
Message-ID: <51A38257.2020804@colorfullife.com> (raw)
In-Reply-To: <1369601453.2259.15.camel@buesod1.americas.hpqcorp.net>
Hi Davidlohr,
On 05/26/2013 10:50 PM, Davidlohr Bueso wrote:
>
> In lack of getting my swingbench DSS environment back, I ran these
> changes against the semop-multi program on my laptop. For 256 threads,
> with Manfred's patchset the ops/sec suffers around -7.3%.
Could you also check the performance of only patch#1?
I fear that it might be slower than all 4 together.
With regards to semop-multi:
Is this the tool?
http://marc.info/?l=linux-kernel&m=136208613626892&q=p3
I think the logic is the wrong:
Locking a semaphore is substraction, unlocking adding.
Thus multiple tasks can run in parallel - and the task switch code is
never triggered.
Could you double check that the number of context switches matches the
output?
I usually use this tool:
http://marc.info/?l=linux-kernel&m=125038376609750
--
Manfred
next prev parent reply other threads:[~2013-05-27 15:57 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-26 9:08 [PATCH 0/4] ipc/sem.c: Bug fixes, regression fixes, v3 Manfred Spraul
2013-05-26 9:08 ` [PATCH 1/4] ipc/sem.c: Fix missing wakeups in do_smart_update_queue() Manfred Spraul
2013-05-27 17:51 ` Rik van Riel
2013-05-27 19:53 ` Manfred Spraul
2013-05-26 9:08 ` [PATCH 2/4] ipc/sem: seperate wait-for-zero and alter tasks into seperate queues Manfred Spraul
2013-05-27 17:57 ` Rik van Riel
2013-06-01 9:20 ` Manfred Spraul
2013-06-01 10:03 ` Mike Galbraith
2013-06-01 10:05 ` Mike Galbraith
2013-06-01 11:04 ` Mike Galbraith
2013-06-01 11:52 ` Manfred Spraul
2013-05-26 9:08 ` [PATCH 3/4] ipc/sem.c: Always use only one queue for alter operations Manfred Spraul
2013-05-27 18:00 ` Rik van Riel
2013-05-26 9:08 ` [PATCH 4/4] ipc/sem.c: Rename try_atomic_semop() to perform_atomic_semop(), docu update Manfred Spraul
2013-05-27 17:59 ` Rik van Riel
2013-05-26 17:37 ` [PATCH 0/4] ipc/sem.c: Bug fixes, regression fixes, v3 Linus Torvalds
2013-05-26 20:50 ` Davidlohr Bueso
2013-05-26 22:59 ` Linus Torvalds
2013-05-27 15:57 ` Manfred Spraul [this message]
2013-05-28 20:37 ` Davidlohr Bueso
2013-05-27 2:04 ` Greg KH
2013-05-27 17:50 ` Rik van Riel
2013-05-27 19:57 ` Greg KH
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