From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932596AbWFIXrg (ORCPT ); Fri, 9 Jun 2006 19:47:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932599AbWFIXrg (ORCPT ); Fri, 9 Jun 2006 19:47:36 -0400 Received: from omx2-ext.sgi.com ([192.48.171.19]:9394 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S932596AbWFIXrf (ORCPT ); Fri, 9 Jun 2006 19:47:35 -0400 Message-ID: <448A089C.6020408@engr.sgi.com> Date: Fri, 09 Jun 2006 16:47:40 -0700 From: Jay Lan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.13) Gecko/20060411 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrew Morton CC: nagar@watson.ibm.com, balbir@in.ibm.com, jlan@sgi.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> <4489F93E.6070509@engr.sgi.com> <20060609162232.2f2479c5.akpm@osdl.org> In-Reply-To: <20060609162232.2f2479c5.akpm@osdl.org> X-Enigmail-Version: 0.90.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: >Jay Lan wrote: > >>If you can show me how to not sending per-tgid with current patchset, >>i would be very happy to drop this request. >> > >pleeeze, not a global sysctl. It should be some per-client subscription thing. > Per-client subscription is not possible since it is the push (multicast) model we talk about and delayacct needs tgid. >But the overhead at present is awfully low. If we don't need this ability >at present (and I don't think we do) then a paper design would be >sufficient at this time. As long as we know we can do this in the future >without breaking existing APIs then OK. > i can see if an exiting process is the only process in the thread group, the (not is_thread_group) condition would be true. So, that leaves multi-threaded applications that are not interested in tgid-data still receive 2x taskstats data. Is a system-wide switch that bad? A site that needs tgid stats can live with the performance consequence while those do not need tgid can enjoy a pure per-task stats data. (I would argue that a thread group is some sort of task aggregate.) How about sending tgid stats when the last process in the group exist? But do not send it if not the last in the thread? Thanks, - jay