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From: Romain Francoise <romain@orebokech.com>
To: Tahsin Erdogan <tahsin@google.com>
Cc: Jens Axboe <axboe@kernel.dk>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] block: Make CFQ default to IOPS mode on SSDs
Date: Tue, 09 Jun 2015 12:18:32 +0200	[thread overview]
Message-ID: <873821kww7.fsf@orebokech.com> (raw)
In-Reply-To: <1432068921-17184-1-git-send-email-tahsin@google.com> (Tahsin Erdogan's message of "Tue, 19 May 2015 13:55:21 -0700")

Hi,

On Tue, May 19, 2015 at 01:55:21PM -0700, Tahsin Erdogan wrote:
> --- a/block/cfq-iosched.c
> +++ b/block/cfq-iosched.c
> @@ -4460,7 +4460,7 @@ static int cfq_init_queue(struct request_queue *q, struct elevator_type *e)
>  	cfqd->cfq_slice[1] = cfq_slice_sync;
>  	cfqd->cfq_target_latency = cfq_target_latency;
>  	cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
> -	cfqd->cfq_slice_idle = cfq_slice_idle;
> +	cfqd->cfq_slice_idle = blk_queue_nonrot(q) ? 0 : cfq_slice_idle;
>  	cfqd->cfq_group_idle = cfq_group_idle;
>  	cfqd->cfq_latency = 1;
>  	cfqd->hw_tag = -1;

Did you test this patch with regular AHCI SSD devices? Applying it on
top of v4.1-rc7 makes no difference, slice_idle is still initialized to
8 in my setup, while rotational is 0.

Isn't the elevator initialized long before the non-rotational flag is
actually set on the device (which probably happens after it's probed on
the scsi bus)?

  parent reply	other threads:[~2015-06-09 10:27 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-19 20:55 [PATCH] block: Make CFQ default to IOPS mode on SSDs Tahsin Erdogan
2015-05-27 20:14 ` Tahsin Erdogan
2015-06-05 22:58   ` Tahsin Erdogan
2015-06-06  1:20     ` Jens Axboe
2015-06-09 10:18 ` Romain Francoise [this message]
2015-06-09 17:42   ` Jens Axboe
2015-06-09 21:54     ` Tahsin Erdogan
2015-06-10  6:44     ` Romain Francoise
2015-06-10 14:03       ` Jens Axboe

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