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Date:      Tue, 3 Jun 2014 11:22:52 -0700
From:      John-Mark Gurney <jmg@funkthat.com>
To:        Warner Losh <imp@bsdimp.com>
Cc:        freebsd-scsi@freebsd.org
Subject:   Re: Review needed
Message-ID:  <20140603182252.GF31367@funkthat.com>
In-Reply-To: <D530E825-A507-41D6-9ABE-A2A7F8F95394@bsdimp.com>
References:  <D530E825-A507-41D6-9ABE-A2A7F8F95394@bsdimp.com>

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Warner Losh wrote this message on Mon, Jun 02, 2014 at 10:46 -0600:
> The code that combines adjacent ranges for BIO_DELETEs to optimize
> trims to the device assumes the list is sorted. Don't apply the
> optimization of not sorting the queue when we have SSDs to the
> delete_queue, since it causes more discard traffic to the drive. While

I'm puzzled by this statement, if I remove the double negative, I get:
Do apply the optimization of sorting the queue when we have SSDs to the
delete_queue, since it (what the new optimizations?) causes more discard
traffic to the drive.

Do you mean previously?

> one could argue that the higher levels should coalesce the trims,
> that's not done today, so some optimization at this level is needed.
> 
> Diffs and a (hopefully) cool review tool: https://phabric.freebsd.org/D142

Please include a raw diff...  A Phabric is only for FreeBSD committers,
it takes the rest of the community out of the ability to review.

Thanks.

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."



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