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Date:      Thu, 22 Feb 2018 08:15:25 +0000
From:      Steven Hartland <steven.hartland@multiplay.co.uk>
To:        Warner Losh <imp@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   Re: svn commit: r329812 - head/sys/cam
Message-ID:  <2666dfe3-28af-06e2-2992-c57b6ba11c12@multiplay.co.uk>
In-Reply-To: <201802220543.w1M5hL8Q068794@repo.freebsd.org>
References:  <201802220543.w1M5hL8Q068794@repo.freebsd.org>

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In our experience this is very device dependent, what lead you to this 
conclusion?

On 22/02/2018 05:43, Warner Losh wrote:
> Author: imp
> Date: Thu Feb 22 05:43:20 2018
> New Revision: 329812
> URL: https://svnweb.freebsd.org/changeset/base/329812
>
> Log:
>    Don't sort TRIMs.
>    
>    While the code for ada and da both assume that the trim list is
>    ordered when doing the coaleascing the TRIMs, it turns out that
>    creating the sorted list uses more resources than are saved by having
>    slightly fewer trims sent to the device.
>    
>    Sponsored by: Netflix
>
> Modified:
>    head/sys/cam/cam_iosched.c
>
> Modified: head/sys/cam/cam_iosched.c
> ==============================================================================
> --- head/sys/cam/cam_iosched.c	Thu Feb 22 04:30:52 2018	(r329811)
> +++ head/sys/cam/cam_iosched.c	Thu Feb 22 05:43:20 2018	(r329812)
> @@ -1392,7 +1392,7 @@ cam_iosched_queue_work(struct cam_iosched_softc *isc,
>   	 * the work on the bio queue.
>   	 */
>   	if (bp->bio_cmd == BIO_DELETE) {
> -		bioq_disksort(&isc->trim_queue, bp);
> +		bioq_insert_tail(&isc->trim_queue, bp);
>   #ifdef CAM_IOSCHED_DYNAMIC
>   		isc->trim_stats.in++;
>   		isc->trim_stats.queued++;
>




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