Message-ID: <1362554072.7242.10.camel@buesod1.americas.hpqcorp.net>
Subject: Re: [PATCH v2 0/4] ipc: reduce ipc lock contention
From: Davidlohr Bueso <davidlohr.bueso@hp.com>
To: Rik van Riel <riel@redhat.com>
Cc: Waiman Long <Waiman.Long@hp.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Emmanuel Benisty <benisty.e@gmail.com>,
        "Vinod, Chegu" <chegu_vinod@hp.com>, "Low, Jason" <jason.low2@hp.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andrew Morton <akpm@linux-foundation.org>, aquini@redhat.com,
        Michel Lespinasse <walken@google.com>, Ingo Molnar <mingo@kernel.org>,
        Larry Woodman <lwoodman@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 05 Mar 2013 23:14:32 -0800
In-Reply-To: <5136BDC1.70804@redhat.com>
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On Tue, 2013-03-05 at 22:53 -0500, Rik van Riel wrote:
> On 03/05/2013 10:46 PM, Waiman Long wrote:
> > On 03/05/2013 03:53 PM, Rik van Riel wrote:
> 
> >> Indeed.  Though how well my patches will work with Oracle will
> >> depend a lot on what kind of semctl syscalls they are doing.
> >>
> >> Does Oracle typically do one semop per semctl syscall, or does
> >> it pass in a whole bunch at once?
> >
> > i had collected a strace log of Oracle instance startup a while ago. In
> > the log, almost all of the semctl() call is to set a single semaphore
> > value in one of the element of the array using SETVAL. Also there are
> > far more semtimedop() than semctl(), about 100:1. Again, all the
> > semtimedop() operations are on a single element of the semaphore array.
> 
> That is good to hear. Just what I was hoping when I started
> working on my patches. You should expect them tomorrow or
> Thursday.

Great, looking forward.

Thanks,
Davidlohr


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