Re: 2.4.14-pre6

From: Helge Hafting (helgehaf@idb.hist.no)
Date: Fri Nov 02 2001 - 03:00:26 EST


Andrew Morton wrote:

> Another potential microoptimisation would be to write out
> clean blocks if that helps merging. So if we see a write
> for blocks 1,2,3,5,6,7 and block 4 is known to be in memory,
> then write it out too. I suspect this would be a win for
> ATA but a loss for SCSI. Not sure.
>

A not to stupid disk would implement the seek to block 5
as waiting for block 4 to move past. So
rewriting block 4 probably wouldn't help. could be
interesting to see a benchmark for that though, perhaps
some drives are really dumb.

The average "half rotation delay" when seeking does not apply
when the seek _isn't_ random.

Helge Hafting
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