Re: [PATCH 1/2] ipc semaphores: reduce ipc_lock contention in semtimedop

Chris Mason
2010-04-15T16:36:15Z

On Thu, Apr 15, 2010 at 06:33:13PM +0200, Manfred Spraul wrote:
> On 04/14/2010 09:50 PM, Chris Mason wrote:
> >On a big system I saw about 4000 semaphores total. The database will
> >just allocate as many as it can into a single array and keep creating
> >arrays until it has all it needs.
> >
> What happens if SEMMSL is reduced (first entry in /proc/sys/kernel/sem)?

Performance improves slightly but the ipc lock is still at the top of the
profile ;)

-chris