From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Nelson Subject: Re: speed decrease since firefly,giant,hammer the 2nd try Date: Tue, 10 Feb 2015 13:10:07 -0600 Message-ID: <54DA578F.3000900@redhat.com> References: <54DA541E.9000608@profihost.ag> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:48268 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751220AbbBJTKY (ORCPT ); Tue, 10 Feb 2015 14:10:24 -0500 In-Reply-To: <54DA541E.9000608@profihost.ag> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Stefan Priebe , "ceph-devel@vger.kernel.org" On 02/10/2015 12:55 PM, Stefan Priebe wrote: > Hello, > > last year in june i already reported this but there was no real result. > (http://lists.ceph.com/pipermail/ceph-users-ceph.com/2014-July/041070.html) > > I then had the hope that this will be fixed itself when hammer is > released. Now i tried hammer an the results are bad as before. > > Since firefly librbd1 / librados2 are 20% slower for 4k random iop/s > than dumpling - this is also the reason why i still stick to dumpling. > > I've now modified my test again to be a bit more clear. > > Ceph cluster itself completely dumpling. > > librbd1 / librados from dumpling (fio inside qemu): 23k iop/s for random > 4k writes > > - stopped qemu > - cp -ra firefly_0.80.8/usr/lib/librados.so.2.0.0 /usr/lib/ > - cp -ra firefly_0.80.8/usr/lib/librbd.so.1.0.0 /usr/lib/ > - start qemu > > same fio, same qemu, same vm, same host, same ceph dumpling storage, > different librados / librbd: 16k iop/s for random 4k writes > > What's wrong with librbd / librados2 since firefly? Hi Stephen, Just off the top of my head, some questions to investigate: What happens to single op latencies? Does enabling/disabling RBD cache have any effect? How's CPU usage? (Does perf report show anything useful?) Can you get trace data? Mark > > Greets, > Stefan > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html