Messages in this thread | | | Date | Sun, 29 May 2005 21:06:08 +0200 | From | Jens Axboe <> | Subject | Re: Playing with SATA NCQ |
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On Sun, May 29 2005, Michael Thonke wrote: > Jens Axboe schrieb: > > >There's really nothing to be tuned. If NCQ is enabled for your drive, it > >will be printed in dmesg after the lba48 flag, such as: > > > >ata1: dev 0 ATA, max UDMA/133, 488281250 sectors lba48 ncq > > > >If you don't see NCQ there, your drive/controller doesn't support it. > >Likewise you will have a queueing depth of > 1 if NCQ is enabled, check > >/sys/block/sdX/device/queue_depth to see what the configured queueing > >depth is for that device. > > > > > > > Hello again, > > the queue_depth of 30 is okay? On boot the CFQ scheduler tells:
By default, the maximum depth is used. For desktop use, a depth of 2-4 is probably more appropriate until the io schedulers become a little more intelligent wrt queueing.
> cfq: depth 4 reached, tagging now on > > This only appears with AHCI enabled what does that mean?
It only appears if AHCI is enabled, because tagged command queueing is only working/enabled on AHCI. The message is informational only, CFQ tells you that it has detected queueing hardware (driver maintains a depth of >= 4).
> Also a question which options can be set in queue_type?
Nothing.
-- Jens Axboe
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