From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bernd Schubert Subject: Re: single cpu thread performance limit? Date: Thu, 11 Aug 2011 21:04:12 +0200 Message-ID: <4E4427AC.6070005@fastmail.fm> References: Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: mark delfman Cc: Linux RAID Mailing List List-Id: linux-raid.ids On 08/11/2011 05:58 PM, mark delfman wrote: > I seem to have hit a significant hard stop in MD RAID1/10 performance > which seems to be linked to a single CPU thread. > > I am using extremely high speed (IOPS) internal block devices =96 8 i= n > total. They are capable of achieving> 1million iops. > > However if I use RAID1 / 10 then MD seems to use a single thread whic= h > will reach 100% CPU utilisation (single core) at around 200K IOPS. > Limiting the entire performance to around 200K. > Out of interest, could you please run "perf top" to let us see where th= e=20 kernel is busy? Thanks, Bernd -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html