Re: [patch 1/1] raid5: speedup sync_request processing

[NeilBrown <neilb@suse.de>]

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On Mon, 9 Jun 2014 17:06:19 -0700 Eivind Sarto <eivindsarto@gmail.com> wrote:

> Ignore previous email.  Forgot to attach patch.
> 
> This is a trivial patch that improves rebuild/resync speed of raid5 arrays.
> Instead of having the resync-thread handle the stripe, it now just sets STRIPE_HANDLE and
> releases the stripe.  Allowing the resync-thread to return immediately and schedule more operations.
> 
> The speedup will increase with more drives in the array.  And it will increase further if additional
> kworker threads are enabled.  But, it improves with just the default raid5d() running.
> 
> Note: I posted this patch a while back, but nothing happened.  Not accepted, not rejected.
> 
> Trying one more time.
> 
> -eivind

I looked through my mail and found you posted much the same patch on 11th
February.
I replied as below.  You never resent (or if you did, I never got it).  You
did reply with some numbers, but that isn't the same as resubmitting the
patch with a proper description at the top.

Your new patch does mention some performance numbers in the comment so that I
a lot better.  I've applied it.

Thanks,
NeilBrown


Hi,
 thanks for the patch.
 When you include a patch as an attachment, I find it easier to work with if
 it is "text/plain" rather than "application/octet-stream".

 As your patch is justified as a performance improvement, please include
 some measurements together with a rough description of the hardware (one or
 two sentences).

 Also, the performance improvement requires that multi-threading is enabled,
 which isn't the default.  Please measure the effect of the patch when
 multi-threading not enabled.
 Maybe we should make the change you suggest be conditional on threading
 being enabled, but we can't know without numbers.

Thanks,
NeilBrown


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