poor ATA disk speed with ICH2

[Kevin Oberman]

> Date: Thu, 09 Sep 2004 22:37:31 +0200
> From: =?ISO-8859-1?Q?S=F8ren_Schmidt?= <sos at DeepCore.dk>
> 
> Kevin Oberman wrote:
> 
> > Here are the results of my last test back in May plus tests done on a
> > kernel built from sources downloaded on Sep. 6. Is that going to catch
> > your fix? I don't see much difference. Do you have version number I can=
> 
> > check?
> 
> Sep 6 should be fine if we are talking -current, on RELENG_5 it=20
> "depends" since the MFC was done on the 6'th..
> >=20
> > Buffer	V4 Read	  V4 Write  V5 Read	V5 Write		=20
> > 512	 8385790  8111781    6921714	 5115853   7130873   5261294
> > 1k	15457027  14865113  12330562	 7811422  12494677   7952281
> > 2k	25677856  25273251  19939822	10572186  20137339  10708676
> > 4k	27083255  25897711  27096896	12860586  27064850  12982472
> > 8k	27079563  26033768  27097726	14416520  27017494  14497783
> > 16k	27082575  Oops!	    27082273	15316924  26936316  15374888
> > 32k	27080720  25908336  27100118	15816203  26977041  15853140
> > 64k	27079904  26008387  27096093	16073422  26939153  15938326
> > 128k	27055901  25928520  27095673	16073422
> > 256k	27076467  25918950  27090967	16118789
> > 512k	27045087  25987266  27077925	16006708
> > 1m	27026694  25738575  27060626	15879266
> >=20
> > Read: dd if=3D/dev/ad2 of=3D/dev/null bs=3Dnnn
> > Write:dd if=3D/dev/zero of=3D/dev/ad2 bs=3Dnnn
> > All tests run for about 30 seconds.
> > All tests in single-user mode. Nothing on ad2 is mounted.
> > Debug (WITNESS, INVARIANTS, malloc checking) disabled.
> 
> > While the test is running, the disk being written to "sings" with the
> > frequency somewhat dependent on the size of the write. On read, I get
> > silence. When I copy my full disk (if=3Dad0 of=3Dad2), I can clearly he=
> ar
> > the sound of the actuator moving the heads constantly toward the end of=
> 
> > the backup. I assume that they are being returned to track 0 on a
> > repeated basis.
> 
> There should be no seeks on a lone write to the raw disk, if there is=20
> you have HW problems as the driver doesn't issue any seeks at all then.
> 
> What disks are this BTW ?

This was RELENG_5 on the 6th at 22:55 UTC. cvsup from my local mirror,
so it may have been up to about 70 minutes old.

The "singing" only happens when running V5. I have no such sound when I
do the same thing with V4. 

The disk is an Toshiba MK4019GAX. 40 GB ATA100 5400RPM. I get the same
performance, though, when using an IBM (now Hitachi) 40GB, ATA100
5400RPM drive. What I am seeing looks a lot like what Bjoern was seeing,
so it's not unique to this system.

Once again, it's fine on V4. 

And, it works on Windows.  (I just had to say that. I have not
actually tested under Windows.)
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634