Re: [PATCH] speed up SATA

Jeff Garzik
2004-03-28T17:24:26Z

Jamie Lokier wrote:
> Jeff Garzik wrote:
>
>>TCQ-on-write for ATA disks is yummy because you don't really know what
>>the heck the ATA disk is writing at the present time. By the time the
>>Linux disk scheduler gets around to deciding it has a nicely merged and
>>scheduled set of requests, it may be totally wrong for the disk's IO
>>scheduler. TCQ gives the disk a lot more power when the disk integrates
>>writes into its internal IO scheduling.
>
>
> Does TCQ-on-write allow you to do ordered write commits, as with barriers,
> but without needing full cache flushes, and still get good performance?

Nope, TCQ is just a bunch of commands rather than one. There are no
special barrier indicators you can pass down with a command.

Jeff