From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx181.postini.com [74.125.245.181]) by kanga.kvack.org (Postfix) with SMTP id EB62D6B0062 for ; Tue, 6 Dec 2011 16:06:11 -0500 (EST) Received: by vbbfn1 with SMTP id fn1so3537843vbb.14 for ; Tue, 06 Dec 2011 13:06:10 -0800 (PST) Date: Tue, 6 Dec 2011 13:06:07 -0800 (PST) From: David Rientjes Subject: Re: [PATCH 1/3] slub: set a criteria for slub node partial adding In-Reply-To: <1323076965.16790.670.camel@debian> Message-ID: References: <1322814189-17318-1-git-send-email-alex.shi@intel.com> <1323076965.16790.670.camel@debian> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: "Alex,Shi" Cc: Christoph Lameter , "penberg@kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Andi Kleen On Mon, 5 Dec 2011, Alex,Shi wrote: > Previous testing depends on 3.2-rc1, that show hackbench performance has > no clear change, and netperf get some benefit. But seems after > irqsafe_cpu_cmpxchg patch, the result has some change. I am collecting > these results. > netperf will also degrade with this change on some machines, there's no clear heuristic that can be used to benefit all workloads when deciding where to add a partial slab into the list. Cache hotness is great but your patch doesn't address situations where frees happen to a partial slab such that they may be entirely free (or at least below your 1:4 inuse to nr_objs threshold) at the time you want to deactivate the cpu slab. I had a patchset that iterated the partial list and found the "most free" partial slab (and terminated prematurely if a threshold had been reached, much like yours) and selected that one, and it helped netperf 2-3% in my testing. So I disagree with determining where to add a partial slab to the list at the time of free because it doesn't infer its state at the time of cpu slab deactivation. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org