From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx142.postini.com [74.125.245.142]) by kanga.kvack.org (Postfix) with SMTP id D1EB26B0088 for ; Tue, 3 Jan 2012 14:00:18 -0500 (EST) Received: by vcge1 with SMTP id e1so15624628vcg.14 for ; Tue, 03 Jan 2012 11:00:17 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <4F033F44.6020403@gmail.com> References: <1325499859-2262-1-git-send-email-gilad@benyossef.com> <1325499859-2262-9-git-send-email-gilad@benyossef.com> <4F033F44.6020403@gmail.com> Date: Tue, 3 Jan 2012 21:00:17 +0200 Message-ID: Subject: Re: [PATCH v5 8/8] mm: add vmstat counters for tracking PCP drains From: Gilad Ben-Yossef Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: linux-kernel@vger.kernel.org, Christoph Lameter , Chris Metcalf , Peter Zijlstra , Frederic Weisbecker , linux-mm@kvack.org, Pekka Enberg , Matt Mackall , Sasha Levin , Rik van Riel , Andi Kleen , Mel Gorman , Andrew Morton , Alexander Viro , Avi Kivity 2012/1/3 KOSAKI Motohiro : > (1/2/12 5:24 AM), Gilad Ben-Yossef wrote: >> This patch introduces two new vmstat counters: pcp_global_drain >> that counts the number of times a per-cpu pages global drain was >> requested and pcp_global_ipi_saved that counts the number of times >> the number of CPUs with per-cpu pages in any zone were less then >> 1/2 of the number of online CPUs. >> >> The patch purpose is to show the usefulness of only sending an IPI >> asking to drain per-cpu pages to CPUs that actually have them >> instead of a blind global IPI. It is probably not useful by itself. ... =A0 =A0 =A0 =A0 =A0 =A0 } >> =A0 =A0 =A0 on_each_cpu_mask(cpus_with_pcps, drain_local_pages, NULL, 1)= ; >> + >> + =A0 =A0 count_vm_event(PCP_GLOBAL_DRAIN); >> + =A0 =A0 if (cpumask_weight(cpus_with_pcps)< =A0(cpumask_weight(cpu_onl= ine_mask) / 2)) >> + =A0 =A0 =A0 =A0 =A0 =A0 count_vm_event(PCP_GLOBAL_IPI_SAVED); > > NAK. > > PCP_GLOBAL_IPI_SAVED is only useful at development phase. I can't > imagine normal admins use it. As the description explains, the purpose of the patch is to show why i claim the previous patch is useful. I did not meant it to be applied to mainline. My apologies for not stating this more clearly. I agree it is not useful for an admin, although perhaps PCP_GLOBAL_DRAIN alone might - I am not sure? Gilad --=20 Gilad Ben-Yossef Chief Coffee Drinker gilad@benyossef.com Israel Cell: +972-52-8260388 US Cell: +1-973-8260388 http://benyossef.com "Unfortunately, cache misses are an equal opportunity pain provider." -- Mike Galbraith, LKML -- 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