From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: Re: [PATCH RFC] blkcg: prepare blkcg knobs for default hierarchy Date: Wed, 23 Apr 2014 14:58:35 -0400 Message-ID: <20140423185835.GD22755@redhat.com> References: <20140413013209.GC26252@mtj.dyndns.org> <20140414180824.GB9552@redhat.com> <20140414193214.GC16835@htj.dyndns.org> <20140415135359.GA13033@redhat.com> <20140415140650.GI1863@htj.dyndns.org> <20140415141826.GB17018@redhat.com> <20140423170141.GJ4781@htj.dyndns.org> <20140423171720.GF24651@redhat.com> <20140423185231.GA4163@mtj.dyndns.org> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20140423185231.GA4163-9pTldWuhBndy/B6EtB590w@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tejun Heo Cc: Jens Axboe , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Li Zefan , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Wed, Apr 23, 2014 at 02:52:31PM -0400, Tejun Heo wrote: > Hello, > > On Wed, Apr 23, 2014 at 01:17:20PM -0400, Vivek Goyal wrote: > > I think we should just require two. One for measuring rate in terms > > of IOPS and other for measuring rate in terms of [kMG]B/sec. > > I meant between cfq and blk-throttle. Why do we have separate stats > for them to present ultimately the same numbers? Oh, sorry, I had misunderstood your question. - Number of IOs serviced will be different at throttling layer and CFQ layer as throttling accounts IO in terms of bios and CFQ accounts in terms of number of requests. - CFQ might not be operational on a device while throttling might be on and one needs bytes stats. - In a custom kernel throttling might not be on and CFQ is on and one needs the stats. So I think we do require duplication of some stats across throttling and CFQ, isn't it? Thanks Vivek