Date: Thu, 15 Dec 2005 17:59:57 +0000 From: Dieter <freebsd@sopwith.solgatos.com> To: freebsd-questions@freebsd.org Subject: NCQ Re: Disk write caching, hw.ata.wc and atacontrol disagree) Message-ID: <200512160159.BAA11562@sopwith.solgatos.com>
next in thread | raw e-mail | index | archive | help
>> So hw.ata.wc thinks that the disk write cache is off, >> but atacontrol cap thinks the disk write cache is on? > I remember this is working but there was a reporting problem > in atacontrol. Looks like "atacontrol cap" reports the state of the disk *before* hw.ata.wc took effect. It would be less confusing if "atacontrol cap" reported the state of the disk at the time atacontrol is run. > You should easily be able to tell whether it is on or off by the > write performance. It should plummet by a factor of 4 or so. I'm seeing only ~10% of the performance I get with the write cache on. Which leads to: Feature Support Enable Value Vendor Native Command Queuing (NCQ) yes - 31/0x1F Where is the knob to turn on NCQ? My controller and disks claim to support it, but grepping the 6.0 man pages finds nothing.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200512160159.BAA11562>