[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 10 Oct 2013 00:33:15 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>,
Oleg Nesterov <oleg@...hat.com>,
Paul McKenney <paulmck@...ux.vnet.ibm.com>,
Mel Gorman <mgorman@...e.de>, Rik van Riel <riel@...hat.com>,
Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
Andrea Arcangeli <aarcange@...hat.com>,
Johannes Weiner <hannes@...xchg.org>,
Thomas Gleixner <tglx@...utronix.de>,
Steven Rostedt <rostedt@...dmis.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/6] Optimize the cpu hotplug locking -v2
On Thu, 10 Oct 2013 09:27:57 +0200 Ingo Molnar <mingo@...nel.org> wrote:
> > > Should be fairly straightforward to test: the sys_sched_getaffinity()
> > > and sys_sched_setaffinity() syscalls both make use of
> > > get_online_cpus()/put_online_cpus(), so a testcase frobbing affinities
> > > on N CPUs in parallel ought to demonstrate scalability improvements
> > > pretty nicely.
> >
> > Well, an in-kernel microbenchmark which camps in a loop doing get/put
> > would measure this as well.
> >
> > But neither approach answers the question "how useful is this patchset".
>
> Even ignoring all the other reasons cited, sys_sched_getaffinity() /
> sys_sched_setaffinity() are prime time system calls, and as long as the
> patches are correct, speeding them up is worthwhile.
That I would not have guessed. What's the use case for calling
get/set_affinity at high frequency?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists