Hello,
Michael Tokarev wrote:
> 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".
I see. Thanks for testing.
> 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?
No one would know without testing.
> 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)
Well, what the driver does is minimal. It just passes through all the
commands to the harddrive. After all, NCQ/TCQ gives the harddrive more
responsibility regarding request scheduling.
--
tejun
-
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]
