From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750742AbWFGCzr (ORCPT ); Tue, 6 Jun 2006 22:55:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750760AbWFGCzr (ORCPT ); Tue, 6 Jun 2006 22:55:47 -0400 Received: from mta2.srv.hcvlny.cv.net ([167.206.4.197]:27053 "EHLO mta2.srv.hcvlny.cv.net") by vger.kernel.org with ESMTP id S1750742AbWFGCzq (ORCPT ); Tue, 6 Jun 2006 22:55:46 -0400 Date: Tue, 06 Jun 2006 22:55:44 -0400 From: Shailabh Nagar Subject: Re: taskstats interface for accounting In-reply-to: <44863376.5020701@sgi.com> To: Jay Lan Cc: Balbir Singh , Andrew Morton , lkml , csturtiv@sgi.com, jamal Message-id: <44864030.6010906@watson.ibm.com> MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7BIT X-Accept-Language: en-us, en References: <44863376.5020701@sgi.com> User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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. Regards, Shailabh > Regards, > jay