From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030316AbWFUVyw (ORCPT ); Wed, 21 Jun 2006 17:54:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030314AbWFUVyw (ORCPT ); Wed, 21 Jun 2006 17:54:52 -0400 Received: from smtp.osdl.org ([65.172.181.4]:65218 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1030312AbWFUVyu (ORCPT ); Wed, 21 Jun 2006 17:54:50 -0400 Date: Wed, 21 Jun 2006 14:54:43 -0700 From: Andrew Morton To: Jay Lan Cc: nagar@watson.ibm.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 Message-Id: <20060621145443.b58daf31.akpm@osdl.org> In-Reply-To: <4499BDDD.3010206@engr.sgi.com> 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> <20060621133838.12dfa9f8.akpm@osdl.org> <4499BAA9.3000707@watson.ibm.com> <4499BDDD.3010206@engr.sgi.com> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.17; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Jun 2006 14:45:01 -0700 Jay Lan wrote: > > Won't it suffice to make delivery of these stats best effort, with > > userspace dealing with missing data, > > How do you recover the missed data? I suspect the best we can do is to let userspace know that data was lost. Is the -ENOBUFS reliable? > > rather than risk delaying exits ? The cases where exits are so > > frequent as in this program should be > > This is very true. However, it was a 2p IA64 machine. I am too frightened to > speak "512p"... If we have 511 CPUs generating data faster than one CPU can handle it, something bad will happen. We either throttle the 511 CPUs or drop data.