Re: [PATCH] 64 bit scsi read/write

Chris Wedgwood
2001-07-15T17:11:02Z

On Sat, Jul 14, 2001 at 09:45:44AM +0100, Alan Cox wrote:

As far as I can tell none of them at least in the IDE world

Can you test with the code I posted a hour or so ago please?

I ask this because I tested writes to:

-- buffered devices

-- ide with caching on

-- ide with caching off

-- scsi (caching on?)

To a buffered device, I get something silly like 63000
writes/second. No big surprises there (other than Linux is bloody lean
these days).

To a SCSI device (10K RPM SCSI-3 160 drive), I get something like 167
writes/second, which seems moderately sane if caching is disabled.

To a cheap IDE drive (5400 RPM?) with caching off, I get about 87
writes/second.

To the same drive, with caching on, I get almost 4000 writes/second.

This seems to imply, at least for my test IDE drive, you can turn
caching off --- and its about half as fast as my SCSI drives which
rotate at about twice the speed (sanity check).

IDE drive: IBM-DTTA-351010, ATA DISK drive
SCSI drive: SEAGATE ST318404LC

--cw