Re: 2.6.20-rc2+: CFQ halving disk throughput.

[Mark Lord]

Jens Axboe wrote:
> > But surely one of (not sure which) sync+async or async+sync may also be 
> > okay?
> > Or would it?
>
> Async merge to sync request should be ok. But I wonder what happens with
> hdparm, since it seems to trigger one of these tests. Very puzzling.
> I'll dive in and take a look.

The code (written 10 years ago) isn't the best in the world,
and will be redone entirely for hdparm-7.0 this year.

But right now, it essentially does this:

loop:
	seek( to sector zero );
	read( 2MBytes );
	repeat loop for 3 seconds

Cheers
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