From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Nelson Subject: Re: less cores more iops / speed Date: Thu, 08 Nov 2012 07:19:18 -0600 Message-ID: <509BB156.5080404@inktank.com> References: <509ADA6A.9000807@profihost.ag> <509AF625.8040207@inktank.com> <509B03EA.9050701@inktank.com> <509B711D.3070206@profihost.ag> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ie0-f174.google.com ([209.85.223.174]:34791 "EHLO mail-ie0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755622Ab2KHNTP (ORCPT ); Thu, 8 Nov 2012 08:19:15 -0500 Received: by mail-ie0-f174.google.com with SMTP id k13so4101773iea.19 for ; Thu, 08 Nov 2012 05:19:13 -0800 (PST) In-Reply-To: <509B711D.3070206@profihost.ag> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Stefan Priebe - Profihost AG Cc: Joao Eduardo Luis , "ceph-devel@vger.kernel.org" On 11/08/2012 02:45 AM, Stefan Priebe - Profihost AG wrote: > Am 08.11.2012 01:59, schrieb Mark Nelson: >> There's also the context switching overhead. It'd be interesting to >> know how much the writer processes were shifting around on cores. > What do you mean by that? I'm talking about the KVM guest not about the > ceph nodes. in this case, is fio bouncing around between cores? > >> Stefan, what tool were you using to do writes? > as always: fio ;-) You could try using numactl to pin fio to a specific core. Also, it may be interesting to try multiple concurrent fio processes, and then concurrent fio processes with each pinned. > > Stefan