Message-ID: <1362645933.2606.14.camel@laptop>
Subject: Re: [PATCH v2 0/4] ipc: reduce ipc lock contention
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Waiman Long <Waiman.Long@hp.com>,
        Davidlohr Bueso <davidlohr.bueso@hp.com>,
        Emmanuel Benisty <benisty.e@gmail.com>,
        "Vinod, Chegu" <chegu_vinod@hp.com>, "Low, Jason" <jason.low2@hp.com>,
        "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>, chris.mason@fusionio.com
Date: Thu, 07 Mar 2013 09:45:33 +0100
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On Tue, 2013-03-05 at 15:53 -0500, 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?

https://oss.oracle.com/~mason/sembench.c

I think Chris wrote that to match a particular pattern of semaphore
operations the database engine in question does. I haven't checked to
see if it triggers the case in point though.

Also, Chris since left Oracle but maybe he knows who to poke.

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