Date: Tue, 17 Apr 2007 08:45:22 -0600 From: Scott Long <scottl@samsco.org> To: "Gelsema, P \(Patrick\) - FreeBSD" <freebsd@superhero.nl> Cc: freebsd-current@freebsd.org, freebsd-hardware@freebsd.org Subject: Re: Difference between 6.2 and 7.0 Adaptec 39320D - 7.0 performing less Message-ID: <4624DD82.7030400@samsco.org> In-Reply-To: <49836.195.50.100.20.1176808326.squirrel@www.superhero.nl> References: <200704162247.29909.gelsemap@superhero.nl> <20070416230322.GA69661@xor.obsecurity.org> <49836.195.50.100.20.1176808326.squirrel@www.superhero.nl>
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Gelsema, P (Patrick) - FreeBSD wrote: > On Tue, April 17, 2007 01:03, Kris Kennaway wrote: >> On Mon, Apr 16, 2007 at 10:47:24PM +0200, Gelsema, P (Patrick) wrote: >>> Goodevening lists, >>> >>> I am toying with Freebsd 7 to see if it will and how it runs on my new >>> Asus >>> M2N mainboard. One of the things I noticed is that when running >>> 7.0-Current-200704 the throughput of the SCSI drive seems halved. When >>> running 6.2 throughput is doubled/normal. >>> >>> Throughput is measured with the following command. >>> >>> dd if=/dev/zero of=/usr/test >>> where /usr resides on da0s1f >>> >>> On 7.0 I get about 33MB/sec >>> On 6.2 I get about 69Mb/sec >>> >>> I did not make any changes, installation is fresh from CD with Minimal >>> as >>> distribution. >> Apparently you weren't paying attention during boot, because 7.0 ships >> with heavy debugging options enabled, and tells you about it up front: >> >> "WARNING: WITNESS option enabled, expect reduced performance.\n"; >> >> Recompile your kernel with debugging options disabled before making >> performance comparisons. >> >> Kris >> > > Ok, what you are saying makes sense. I did see the warnings and the bits > in the kernel config. The thing that triggered me was that when paying > attention during boot the SCSI Disk was detected as only 160.00MB/s > instead of the expected 320.00MB/s. The detection of devices is not > subject to debugging, is it? > > Excerpts from log. > > Freebsd 7 > da0: <SEAGATE ST336753LW HPS2> Fixed Direct Access SCSI-3 device > da0: 160.000MB/s transfers (80.000MHz DT, offset 63, 16 bit) > da0: Command Queueing Enabled > > Freebsd 6.2 > da0: <SEAGATE ST336753LW HPS2> Fixed Direct Access SCSI-3 device > da0: 320.000MB/s transfers (160.000MHz DT, offset 63, 16 bit), Tagged > Queueing Enabled > > Thanks, > The 39320D is a finicky card. I don't recall putting in the code that would downshift the speed like this, but it wouldn't surprise me if it is a side effect of the system going slower. Anyways, it sounds like you're a good candidate/victim for the MPSAFE locking changes that I just made to the SCSI layer and the ahc/ahd drivers. Would you mind testing it out (just update to the latest 7-CURRENT sources) and let me know how it works for you? Scott
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