[PATCH V2 RESEND] fsl-sata: I/O load balancing

[Zang Roy-R61911]

> -----Original Message-----
> From: linuxppc-dev-bounces+tie-fei.zang=freescale.com at lists.ozlabs.org
> [mailto:linuxppc-dev-bounces+tie-fei.zang=freescale.com at lists.ozlabs.org]
> On Behalf Of Benjamin Herrenschmidt
> Sent: Friday, February 17, 2012 11:19 AM
> To: Li Yang-R58472
> Cc: Liu Qiang-B32616; jgarzik at pobox.com; linuxppc-dev at lists.ozlabs.org;
> linux-kernel at vger.kernel.org; linux-ide at vger.kernel.org
> Subject: RE: [PATCH V2 RESEND] fsl-sata: I/O load balancing
> 
> On Fri, 2012-02-17 at 03:09 +0000, Li Yang-R58472 wrote:
> > >I tried a debian install on the p5020ds here and I find SATA to be
> > >extremely slow, generating millions of interrupts. I think the
> > defaults
> > >should be a lot more aggressive at coalescing.
> >
> > The P5020 has a hardware problem with SATA, making it generate more
> > interrupts than it should.  A new revision of the silicon will fix it.
> 
> Ok cool. With a bit of luck you guys can send me a new silicon when it's
> available then :-) (The one in the board you got me seems to be in a
> socket).
Ben,
We still do not have the a P5020 sample to fix the problem.
One workaround is to use the patch ( I think you have noticed the patch):
http://git.freescale.com/git/cgit.cgi/ppc/sdk/linux.git/commit/?id=92c0ce1e599e788ffc0908739db9bd5e0dbdad69

and  use a SSD hard drive.
It will have a usable performance.
Thanks.
Roy