From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754021AbaEOHLW (ORCPT ); Thu, 15 May 2014 03:11:22 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:64957 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345AbaEOHLV (ORCPT ); Thu, 15 May 2014 03:11:21 -0400 Message-ID: <1400137877.5175.147.camel@marge.simpson.net> Subject: Re: [cgroup] a0f9ec1f181: -4.3% will-it-scale.per_thread_ops From: Mike Galbraith To: Tejun Heo Cc: Fengguang Wu , Jet Chen , LKML , lkp@01.org Date: Thu, 15 May 2014 09:11:17 +0200 In-Reply-To: <20140515061422.GC5539@mtj.dyndns.org> References: <5374479F.3050507@intel.com> <20140515045517.GC3825@htj.dyndns.org> <20140515060026.GA12710@localhost> <20140515061422.GC5539@mtj.dyndns.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-05-15 at 02:14 -0400, Tejun Heo wrote: > Hmmm... I'm completely stumped. The commit in question has nothing to > do with tmpfs. It only affects three cgroup files - "tasks", > "cgroup.procs" and "release_agent". It can't possibly have any effect > on tmpfs operation. Maybe random effect through code alignment? Even > that is highly unlikely. Unlikely, but it happens. I bisected a tbench regression down to a completely unrelated driver change, and watched it repeatably drop throughput 5% despite skeptical "No way, show me that trick again". -Mike