Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760900Ab2FHDRe (ORCPT ); Thu, 7 Jun 2012 23:17:34 -0400 Received: from mail-qc0-f174.google.com ([209.85.216.174]:43696 "EHLO mail-qc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754695Ab2FHDRd (ORCPT ); Thu, 7 Jun 2012 23:17:33 -0400 Message-ID: <4FD16EC8.60502@gmail.com> Date: Thu, 07 Jun 2012 23:17:28 -0400 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Anton Vorontsov CC: Pekka Enberg , Leonid Moiseichuk , KOSAKI Motohiro , Minchan Kim , Bartlomiej Zolnierkiewicz , John Stultz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com Subject: Re: [PATCH 1/5] vmstat: Implement refresh_vm_stats() References: <20120601122118.GA6128@lizard> <1338553446-22292-1-git-send-email-anton.vorontsov@linaro.org> In-Reply-To: <1338553446-22292-1-git-send-email-anton.vorontsov@linaro.org> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1051 Lines: 26 (6/1/12 8:24 AM), Anton Vorontsov wrote: > This function forcibly flushes per-cpu vmstat diff counters to the > global counters. > > Note that we don't try to flush percpu pagesets, the pcp will be > still flushed once per 3 seconds. > > Signed-off-by: Anton Vorontsov No. This is insane. Your patch improved vmevent accuracy a _bit_. But instead of, decrease a performance of large systems. That's no good deal. 99% user never uses vmevent. MOREOVER, this patch don't solve vmevent accuracy issue AT ALL. because of, a second is enough big to make large inaccuracy. Modern cpus are fast. Guys, the fact is, user land monitor can't use implicit batch likes vmstat. That's a reason why perf don't use vmstat. I suggest you see perf APIs. It may bring you good inspiration. -- 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/