From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe - Profihost AG Subject: RBD speed vs threads Date: Fri, 15 Jun 2012 07:56:58 +0200 Message-ID: <4FDACEAA.8080306@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.profihost.ag ([85.158.179.208]:35670 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752394Ab2FOF5G (ORCPT ); Fri, 15 Jun 2012 01:57:06 -0400 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: "ceph-devel@vger.kernel.org" Hello list, i still don't understand why the speed of the rados bench depends so heavily on the threads. Right now i get around 100MB/s per thread. So 1 thread is 100MB/s, 4 Threads 400MB/s and 16 threads results an about 1100MB/s. So 1100MB/s is great but i still don't get why 1 thread gets "only" 100MB/s. Total time run: 30.037374 Total writes made: 8326 Write size: 4194304 Bandwidth (MB/sec): 1108.752 Stddev Bandwidth: 47.5612 Max bandwidth (MB/sec): 1152 Min bandwidth (MB/sec): 948 Average Latency: 0.0577107 Stddev Latency: 0.020784 Max latency: 0.382413 Min latency: 0.026057 Stefan