Messages in this thread |  | | | Date | Tue, 12 Jun 2012 23:09:47 +0200 | | From | Jan Kara <> | | Subject | Re: File copy is very slow on linux-3.4.2 (or linux-3.3x) on a specific hardware: AMD FX-8150 + 990FX |
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On Tue 12-06-12 20:39:32, Wallak wrote: > Jan Kara wrote: > >On Mon 11-06-12 21:54:16, wallak@free.fr wrote: > >>I've a very annoying issue on recent kernel (linux-3.4.2-SMP) with my main motherboard (AMD FX-8150 + 990FX - 8 cores 4.1GHz), file copy is very slow (see below). The same kernel works flawlessly on an AMD E450 2 cores motherboard. > >> > >>Linux-3.2.20 works properly on this hardware. > >>hdparm -t gives good results on both kernels. > >> > >>I've no idea where this bug come from. Do you have this issue on your hardware ? A patch is available ? > >> > >> > >>*linux-3.4.2 > >>dd if=../in/file_8gb.tmp of=tmp.tmp bs=1024k count=100 > >>100+0 records in > >>100+0 records out > >>104857600 bytes (105 MB) copied, 132.884 s, 789 kB/s > >> > >> > >>*linux-3.2.20 > >>dd if=../in/file_8gb.tmp of=tmp.tmp bs=1024k count=100 > >>100+0 records in > >>100+0 records out > >>104857600 bytes (105 MB) copied, 3.30793 s, 31.7 MB/s > > So let's separate reading and writing part first. What is the speed of > >dd if=../in/file_8gb.tmp of=/dev/null bs=1M count=100 > > on both kernels? > >And what is the speed of: > >dd if=/dev/zero of=tmp.tm bs=1M count=100 > > You're right, the issue is only while writing. The results are below: > > #linux-3.4.2 > dd if=/dev/zero of=tmp.tm bs=1M count=100 > 100+0 records in > 100+0 records out > 104857600 bytes (105 MB) copied, 151.347 s, 693 kB/s > dd if=../in/file_8gb.tmp of=/dev/null bs=1M count=100 > 100+0 records in > 100+0 records out > 104857600 bytes (105 MB) copied, 1.26228 s, 83.1 MB/s > > #linux-3.2.20 > dd if=/dev/zero of=tmp.tm bs=1M count=100 > 100+0 records in > 100+0 records out > 104857600 bytes (105 MB) copied, 1.00838 s, 104 MB/s > dd if=../in/file_8gb.tmp of=/dev/null bs=1M count=100 > 100+0 records in > 100+0 records out > 104857600 bytes (105 MB) copied, 1.26947 s, 82.6 MB/s > > > > > > Also what filesystems are you using? > > This is an ext2 file system: > > /dev/sda6 ext2 464463364 323380956 141082408 70% /backup OK, I'm surprised by one thing - how come the writes do no end up cached in memory (thus you should get much higher throughput). Is the filesystem mounted with -o sync option by any chance?
Honza -- Jan Kara <jack@suse.cz> SUSE Labs, CR
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