From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tao Guo Subject: Re: async/X threads and rebuild slowdown Date: Tue, 16 Mar 2010 21:24:43 +0800 Message-ID: <318b7ac71003160624m16aad423lddca62c31021b104@mail.gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Jeremy Sanders Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids I also meet this problem in several of my machines. If I change back to kernel 2.6.18, it is OK, but in 2.6.32 kernel, the performance is really poor. At last I found a solution, set CONFIG_MULTICORE_RAID456=3Dn when compiling raid456 module, then everything goes normal. My machines do have multicore cpu, so it is weird :< Maybe there is something wrong with the CONFIG_MULTICORE_RAID456 enable= d code? On Tue, Mar 16, 2010 at 8:41 PM, Jeremy Sanders wrote: > Hi - It seems our MD raid rebuild speeds are very slow with the new F= edora > 2.6.32.9-70 kernel. We're only getting ~13MB/s: > > [root@xback2 ~]# cat /proc/mdstat > Personalities : [raid6] [raid5] [raid4] > md0 : active raid5 sdb1[0] sdj1[10](S) sdk1[9] sdl1[8] sdi1[7] sdh1[6= ] > sdg1[5] sdf1[4] sde1[3] sdd1[2] sdc1[1] > =C2=A0 =C2=A0 =C2=A08788959360 blocks level 5, 32k chunk, algorithm 2= [10/10] [UUUUUUUUUU] > =C2=A0 =C2=A0 =C2=A0[=3D=3D=3D=3D=3D>...............] =C2=A0resync =3D= 29.3% (286397320/976551040) > finish=3D897.2min speed=3D12819K/sec > > The maximum rebuild speed is at the default 200000K/s. The drives are > connected to a 3ware 9650SE-16ML controller on PCI-Express. > > There seem to be hundreds of async/X threads, where X goes up to 129 = at > least. The md0_raid5 process is using at least 80% of the CPU on this= dual > core Athlon 7750 system. > > Has anything changed recently in the kernel. I don't remember md0_rai= d5 > being so processor inefficient, slow at rebuilding or creating hundre= ds of > kernel threads. > > Are these async/X threads documented anywhere? > > Thanks > > Jeremy > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.ht= ml > --=20 tao. -- 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