Sata Performance

Leonardo Sbaraini leonardo.sbaraini at
Mon Jun 30 06:34:48 PDT 2008

* From the T10 Reflector (t10 at, posted by:
* "Leonardo Sbaraini" <leonardo.sbaraini at>
Hi all, I'm list newbie.
Well, for a week I'm researching a way to boost sata data transfer.
Looking in I found some
parameters to change:
   * multcount: Short for multiple sector count. This controls how
many sectors are fetched from the disk in a single I/O interrupt. When
	 this feature is enabled, it typically reduces operating
system overhead for disk I/O by 30-50%. On many systems, it also
provides increased data throughput of anywhere from 5% to 50%.
   * I/O support: This is a big one. This flag controls how data is
passed from the PCI bus to the controller. Almost all modern
controller chipsets support mode 3, or 32-bit mode w/sync. Some even
support 32-bit async.
   * unmaskirq: Turning this on will allow Linux to unmask other
interrupts while processing a disk interrupt. What does that mean? It
lets Linux attend to other interrupt-related tasks (i.e., network
traffic) while waiting for your disk to return with the data it asked
for. It should improve overall system response time, but be warned:
Not all hardware configurations will be able to handle it.
   * using_dma: DMA can be a tricky business. If you can get your
controller and drive using a DMA mode, do it. But I have seen more
than one machine hang while playing with this option.
I started using hdparm to get info:
hdparm /dev/hda
multcount    =	0 (off)
I/O support  =	0 (default 16-bit)
I read and the PDF "sbc3r15" wrote
|from T10 Vice-Chair Mark S. Evans and I still dont know wich parameter
I need to modify with "sdparm" command.
Thanks in advance.
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