Re: Perfromance drop on SCSI hard disk

From: Alex,Shi
Date: Mon May 16 2011 - 04:38:58 EST

> > what I mean is current sdev (other devices too) can still be added into
> > starved list, so only does async execute for current q isn't enough,
> > we'd better put whole __scsi_run_queue into workqueue. something like
> > below on top of yours, untested. Not sure if there are other recursive
> > cases.
> verified the regression can be fully fixed by your patch (with my
> suggested fix to avoid race). Can we put a formal patch upstream?

Yes, we tested Jens patch alone and plus Shaohua's patch too. Both of
them recovered SAS disk performance too. Now I am testing them on SSD
disk with kbuild and fio cases, In theory, they will both work.

> Thanks,
> Shaohua

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at