From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750928AbWFXDI2 (ORCPT ); Fri, 23 Jun 2006 23:08:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750935AbWFXDI2 (ORCPT ); Fri, 23 Jun 2006 23:08:28 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:7819 "EHLO e3.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1750928AbWFXDI2 (ORCPT ); Fri, 23 Jun 2006 23:08:28 -0400 Message-ID: <449CACA9.60609@watson.ibm.com> Date: Fri, 23 Jun 2006 23:08:25 -0400 From: Shailabh Nagar User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrew Morton CC: jlan@engr.sgi.com, balbir@in.ibm.com, csturtiv@sgi.com, linux-kernel@vger.kernel.org Subject: Re: [Patch][RFC] Disabling per-tgid stats on task exit in taskstats References: <44892610.6040001@watson.ibm.com> <20060609010057.e454a14f.akpm@osdl.org> <448952C2.1060708@in.ibm.com> <20060609042129.ae97018c.akpm@osdl.org> <4489EE7C.3080007@watson.ibm.com> <449999D1.7000403@engr.sgi.com> <44999A98.8030406@engr.sgi.com> <44999F5A.2080809@watson.ibm.com> <4499D7CD.1020303@engr.sgi.com> <449C2181.6000007@watson.ibm.com> <20060623141926.b28a5fc0.akpm@osdl.org> In-Reply-To: <20060623141926.b28a5fc0.akpm@osdl.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: >On Fri, 23 Jun 2006 13:14:41 -0400 >Shailabh Nagar wrote: > > > >>The results show that differential between tgid on and off >>starts becoming significant once the exit rate crosses roughly 1000 >>threads/second. Below that exit rate, the difference is negligible. >>Above it, the difference starts climbing rapidly. >> >>So I guess the question is whether this rate of exit is representative >>enough of real life to warrant making any more changes to the existing >>patchset, beyond the locking changes in 2. above. >> >>>>From my limited experience, I think this is too high an exit rate >>to be worrying about overhead. >> >> >> > >1000/sec isn't terribly high. CGI servers, shell scripts. > >And kernel development ;) A `pushpatch 1500' here does 992 fork/exec/exit >per second. > > Don't all of these create new tasks, not threads ? Single-threaded tasks fork/exec/exit'ing is not a problem since per-tgid data is not sent in that case (since it will be identical to the per-tid data). >> %ovhd of tgid on over off >> (higher is worse) >> >>Exit User Sys Elapsed >>Rate Time Time Time >> >>2283 25.76 649.41 -0.14 >>1193 -10.53 88.81 -0.12 >>963 -11.90 3.28 -0.10 >>806 -8.54 -0.84 0.16 >>694 -4.41 2.38 0.03 >> >> > >Oh wow. Something's gone quadratic there. > >