From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joonsoo Kim Subject: Re: [RT LATENCY] 249 microsecond latency caused by slub's unfreeze_partials() code. Date: Wed, 27 Mar 2013 11:59:57 +0900 Message-ID: <20130327025957.GA17125@lge.com> References: <1363906545.6345.81.camel@gandalf.local.home> <0000013d92c37ff3-5fb85400-bec1-4eda-8ba1-332566884c59-000000@email.amazonses.com> <1364010673.6345.156.camel@gandalf.local.home> <0000013da1f93be3-c3d42ae8-ff34-4c63-8094-77a83291ea19-000000@email.amazonses.com> <1364227073.6345.182.camel@gandalf.local.home> <1364228039.6345.183.camel@gandalf.local.home> <0000013da2ace21a-9e87fe8a-75c2-4b7c-b5e1-37ad196ce012-000000@email.amazonses.com> <1364234613.6345.184.camel@gandalf.local.home> <0000013da2ce20f8-0e3a64ef-67ed-4ab4-9f20-b77980c876c3-000000@email.amazonses.com> <1364236355.6345.185.camel@gandalf.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Lameter , LKML , RT , Thomas Gleixner , Clark Williams To: Steven Rostedt Return-path: Content-Disposition: inline In-Reply-To: <1364236355.6345.185.camel@gandalf.local.home> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On Mon, Mar 25, 2013 at 02:32:35PM -0400, Steven Rostedt wrote: > On Mon, 2013-03-25 at 18:27 +0000, Christoph Lameter wrote: > > On Mon, 25 Mar 2013, Steven Rostedt wrote: > > > > > If this makes it more deterministic, and lower worse case latencies, > > > then it's definitely worth the price. > > > > Yes that would make it more deterministic. Maybe I should add an option > > to be able to compile the allocator without cpu partial page support? > > I agree that would be useful. Hello, Steven and Christoph. How about using spin_try_lock() in unfreeze_partials() and using spin_lock_contented() in get_partial_node() to reduce latency? IMHO, this doesn't make code more deterministic, but can maintain a benefit of cpu partial page with tolerable latency. Thanks. > > -- Steve > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/