Re: SATA kernel-buffered read VERY slow (not raid, Promise TX300card); 2.6.23.1(vanilla)

From: Mark Lord
Date: Tue Jan 01 2008 - 11:06:25 EST



I wanted to use the newer pata support in the SATA lib, but
got frustrated "real fast" by the lack of disk-parameter support
in the new pata library (hdparm is mostly broken; and the SCSI
utils aren't really intended for ATA(or SATA?) disks using the
SCSI interface.
...

Most hdparm flags work perfectly fine with libata,
unless perhaps you're using Fedora, which for some odd
reason was using a 2+ year old copy of hdparm until
very very recently.

As others noted, the only things not working are things that
libata itself chooses not to allow from userspace because libata
has better low-level drivers that can set those things automatically
in a more reliable fashion than we ever could with drivers/ide:
DMA, 32-bit I/O, PIO/DMA xfer rates, hotplug stuff.

The rest, including acoustic and power-saving parameters,
work just fine with libata.

Cheers
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