Tejun Heo wrote:
> Michael Tokarev wrote:
[]
>> A test drive is Seagate Barracuda ST3250620AS "desktop" drive,
>> 250Gb, cache size is 16Mb, 7200RPM.
[test shows that NCQ makes no difference whatsoever]
> And which elevator?
Well. It looks like the results does not depend on the
elevator. Originally I tried with deadline, and just
re-ran the test with noop (hence the long delay with
the answer) - changing linux elevator changes almost
nothing in the results - modulo some random "fluctuations".
In any case, NCQ - at least in this drive - just does
not work. Linux with its I/O elevator may help to
speed things up a bit, but the disk does nothing in
this area. NCQ doesn't slow things down either - it
just does not work.
The same's for ST3250620NS "enterprise" drives.
By the way, Seagate announced Barracuda ES 2 series
(in range 500..1200Gb if memory serves) - maybe with
those, NCQ will work better?
Or maybe it's libata which does not implement NCQ
"properly"? (As I shown before, with almost all
ol'good SCSI drives TCQ helps alot - up to 2x the
difference and more - with multiple I/O threads)
/mjt
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
