Re: [PATCH v2 0/4] ipc: reduce ipc lock contention

From: Davidlohr Bueso
Date: Wed Mar 06 2013 - 02:14:38 EST


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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