Re: Any news on a higher performance sata_sil SIL_QUIRK_MOD15WRITEworkaround?

[Jeff Garzik]

Clem Taylor wrote:
> I've been really disappointed by the performance of the Silicon Image 
> 3114 on my new x86_box. I spent a bunch of time looking into the 
> problem, thinking it was a software RAID5 or xfs issue causing 4K IOs.
> I don't know why I didn't notice the 'applying Seagate errata fix' in 
> dmesg until after I did a bunch of performance testing and realized that 
> it was a sata_sil issue.
>
> So, I was wondering what I can do about this problem? I am not currently 

Get a different controller + disk combination.


> getting enough disk performance to justify the amount spent on the 
> system or enough to satisfy the application I'm working on. Before I go 
> out and purchase a 3ware controller and re-install the machine (ouch), 
> is there any chance of a better work around in the near future? I'd be 
> more than willing to test out a patch.
>
> Is the problem with really with nblocks % 15 == 1? Or is the problem 
> with nblocks % 15 == 0? If it is the later and I'm using xfs with 4K 
> blocks, couldn't I just turn off the workaround or will the RAID5 driver 
> potentially break up larger requests?

The problem is that the Silicon Image controller sends unusual -- but 
legal -- block sizes to the SATA device.

Older Seagates cannot cope with this unique, but spec-correct behavior.

This issue cannot even be worked around with "nblocks % 15 == 1", as was 
previously thought.  Using that formula just makes the problem harder to 
reproduce.

Further, I don't have any plans to address the performance issue, since 
the set of affected drives is finite.


> It would seem that the root of the problem is a Seagate issue. Does 
> anyone know if Seagate fixed the problem with a firmware update? 

You could find out for us, and let us know :)

	Jeff


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/