From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: Re: [PATCH -mmotm 0/5] memcg: per cgroup dirty limit (v7) Date: Wed, 17 Mar 2010 09:34:07 -0400 Message-ID: <20100317133407.GA9198__42892.0826096602$1268832978$gmane$org@redhat.com> References: <1268609202-15581-1-git-send-email-arighi@develer.com> <20100315171209.GI21127@redhat.com> <20100315171921.GJ21127@redhat.com> <20100317115427.GR18054@balbir.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20100317115427.GR18054-SINUvgVNF2CyUtPGxGje5AC/G2K4zDHf@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Balbir Singh Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Andrea Righi , Daisuke Nishimura , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Trond Myklebust , Suleiman Souhlal , Andrew Morton , containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: containers.vger.kernel.org On Wed, Mar 17, 2010 at 05:24:28PM +0530, Balbir Singh wrote: > * Vivek Goyal [2010-03-15 13:19:21]: > > > On Mon, Mar 15, 2010 at 01:12:09PM -0400, Vivek Goyal wrote: > > > On Mon, Mar 15, 2010 at 12:26:37AM +0100, Andrea Righi wrote: > > > > Control the maximum amount of dirty pages a cgroup can have at any given time. > > > > > > > > Per cgroup dirty limit is like fixing the max amount of dirty (hard to reclaim) > > > > page cache used by any cgroup. So, in case of multiple cgroup writers, they > > > > will not be able to consume more than their designated share of dirty pages and > > > > will be forced to perform write-out if they cross that limit. > > > > > > > > > > For me even with this version I see that group with 100M limit is getting > > > much more BW. > > > > > > root cgroup > > > ========== > > > #time dd if=/dev/zero of=/root/zerofile bs=4K count=1M > > > 4294967296 bytes (4.3 GB) copied, 55.7979 s, 77.0 MB/s > > > > > > real 0m56.209s > > > > > > test1 cgroup with memory limit of 100M > > > ====================================== > > > # time dd if=/dev/zero of=/root/zerofile1 bs=4K count=1M > > > 4294967296 bytes (4.3 GB) copied, 20.9252 s, 205 MB/s > > > > > > real 0m21.096s > > > > > > Note, these two jobs are not running in parallel. These are running one > > > after the other. > > > > > > > Ok, here is the strange part. I am seeing similar behavior even without > > your patches applied. > > > > root cgroup > > ========== > > #time dd if=/dev/zero of=/root/zerofile bs=4K count=1M > > 4294967296 bytes (4.3 GB) copied, 56.098 s, 76.6 MB/s > > > > real 0m56.614s > > > > test1 cgroup with memory limit 100M > > =================================== > > # time dd if=/dev/zero of=/root/zerofile1 bs=4K count=1M > > 4294967296 bytes (4.3 GB) copied, 19.8097 s, 217 MB/s > > > > real 0m19.992s > > > > This is strange, did you flish the cache between the two runs? > NOTE: Since the files are same, we reuse page cache from the > other cgroup. Files are different. Note suffix "1". Vivek