From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932466AbWFGXpg (ORCPT ); Wed, 7 Jun 2006 19:45:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932467AbWFGXpg (ORCPT ); Wed, 7 Jun 2006 19:45:36 -0400 Received: from omx2-ext.sgi.com ([192.48.171.19]:12759 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S932466AbWFGXpg (ORCPT ); Wed, 7 Jun 2006 19:45:36 -0400 Message-ID: <44876510.1050808@engr.sgi.com> Date: Wed, 07 Jun 2006 16:45:20 -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: Shailabh Nagar CC: Balbir Singh , Andrew Morton , lkml , csturtiv@sgi.com, jamal Subject: Re: taskstats interface for accounting References: <44863376.5020701@sgi.com> <44864030.6010906@watson.ibm.com> In-Reply-To: <44864030.6010906@watson.ibm.com> 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 Shailabh Nagar wrote: > Jay Lan wrote: > >> Hi Balbir and Shailabh, >> >> I finally have time to think about implementation details of CSA over >> taskstats interface. I took another look at the taskstats interface >> proposal and was a little bit nervous. >> >> Do you remember i suggested to use #ifdef to cut down traffic and i >> was told a generic netlink header would serve the purpose? >> What i see now at Documentation/accounting/taskstats.txt saying >> NETLINK_GENERIC family is used for unicast query/reply mode. The >> NETLINK_GENERIC family provides great flexsibility on what to >> receive. However, CSA only uses the multicast mode to receive from >> kernel >> whenever tasks are existing. I guess i would need to read the netlink >> documentation more carefully to see whether my understanding is >> correct. > > I don't think there's a problem here. The netlink socket opened for > listening to > taskstat data sent on task exit can be done in multicast mode....the > example code in the > Documentation does that. > >> >> Another thing i overlooked when i did the review was that taskstats >> interface is designed to provide _BOTH_ per task _AND_ per thread >> accounting data EVERY TIME a task exists. A thread is an aggregate >> of (per-pid) tasks. Since this type of aggregation is not used in >> CSA, half of data traffic would be useless. Can we add a way to >> configure to not send per-thread data to the socket? > > I don't see why not. We could extend the command set to set tgid > sending on/off. This would be great! But, we can have a number of applications listening on the socket. We surely do not want applications to send conflicting commands to the kernel. Maybe we can make it a /etc/sysconfig option. Regards, - jay > > Regards, > Shailabh > >> Regards, >> jay > >