RE: [PATCH][SDK v1.2] sata: I/O load balancing

From: Liu Qiang-B32616
Date: Fri Jan 13 2012 - 04:57:48 EST



________________________________________
> From: linux-ide-owner@xxxxxxxxxxxxxxx [linux-ide-owner@xxxxxxxxxxxxxxx] on behalf of Li Yang [leoli@xxxxxxxxxxxxx]
> Sent: Friday, January 13, 2012 3:36 AM
> To: Liu Qiang-B32616
> Cc: jgarzik@xxxxxxxxx; linux-ide@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx; Liu Qiang-B32616
> Subject: Re: [PATCH][SDK v1.2] sata: I/O load balancing

> On Fri, Jan 13, 2012 at 4:25 PM, Qiang Liu <qiang.liu@xxxxxxxxxxxxx> wrote:
> > From: Qiang Liu <b32616@xxxxxxxxxxxxx>
> >
> > Reduce interrupt singnals through reset Interrupt Coalescing Control Reg.
> > Increase the threshold value of interrupt and timer will reduce the number
> > of complete interrupt sharply. Improve the system performance effectively.

> There is always a trade off of throughput and latency by using
> interrupt coalescing. It's not reasonable to assume that the
> throughput is the only factor to be considered and set the coalescing
> threshold and timeout to the max value by default. Have you carried
> out other benchmark like copying many small files?
No, I didn't test small file. I think this won't affect system load. I can have a test
and describe the result in next patch.

> It will be safer to make the coalescing runtime configurable like the
> sata_mv driver, IMO.
Ok, I will do it like this in next patch.


- Leo
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