Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755636Ab2FHLD4 (ORCPT ); Fri, 8 Jun 2012 07:03:56 -0400 Received: from smtp.nokia.com ([147.243.1.48]:21304 "EHLO mgw-sa02.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752532Ab2FHLDz (ORCPT ); Fri, 8 Jun 2012 07:03:55 -0400 From: To: CC: , , , , , , , , Subject: RE: [PATCH 2/5] vmevent: Convert from deferred timer to deferred work Thread-Topic: [PATCH 2/5] vmevent: Convert from deferred timer to deferred work Thread-Index: AQHNP/HM8KMmZkc4xkKq2ZDXaeCP2Zbvq0sAgAA7gACAACLOoP//7gqAgAAk2GD//+b9AIAAJPtQ///62gAABLpu8A== Date: Fri, 8 Jun 2012 11:03:29 +0000 Message-ID: <84FF21A720B0874AA94B46D76DB98269045F7C35@008-AM1MPN1-004.mgdnok.nokia.com> References: <20120601122118.GA6128@lizard> <1338553446-22292-2-git-send-email-anton.vorontsov@linaro.org> <4FD170AA.10705@gmail.com> <20120608065828.GA1515@lizard> <84FF21A720B0874AA94B46D76DB98269045F7890@008-AM1MPN1-004.mgdnok.nokia.com> <20120608075844.GA6362@lizard> <84FF21A720B0874AA94B46D76DB98269045F7A24@008-AM1MPN1-004.mgdnok.nokia.com> <20120608084105.GA9883@lizard> <84FF21A720B0874AA94B46D76DB98269045F7B01@008-AM1MPN1-004.mgdnok.nokia.com> <20120608103501.GA15827@lizard> In-Reply-To: <20120608103501.GA15827@lizard> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.22.0.61] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 X-OriginalArrivalTime: 08 Jun 2012 11:03:30.0090 (UTC) FILETIME=[565368A0:01CD4566] X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id q58B42ht025696 Content-Length: 1317 Lines: 25 > -----Original Message----- > From: ext Anton Vorontsov [mailto:cbouatmailru@gmail.com] > Sent: 08 June, 2012 13:35 ... > > Context switches, parsing, activity in userspace even memory situation is > not changed. > > Sure, there is some additional overhead. I'm just saying that it is not drastic. It > would be like 100 sprintfs + 100 sscanfs + 2 context switches? Well, it is > unfortunate... but come on, today's phones are running X11 and Java. :-) Vmstat generation is not so trivial. Meminfo has even higher overhead. I just checked generation time using idling device and open/read test: - vmstat min 30, avg 94 max 2746 uSeconds - meminfo min 30, average 65 max 15961 uSeconds In comparison /proc/version for the same conditions: min 30, average 41, max 1505 uSeconds > > In kernel space you can use sliding timer (increasing interval) + shinker. > > Well, w/ Minchan's idea, we can get shrinker notifications into the userland, > so the sliding timer thing would be still possible. Only as a post-schrinker actions. In case of memory stressing or close-to-stressing conditions shrinkers called very often, I saw up to 50 times per second. ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?