All of lore.kernel.org
 help / color / mirror / Atom feed
From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "osandov@osandov.com" <osandov@osandov.com>,
	"kashyap.desai@broadcom.com" <kashyap.desai@broadcom.com>,
	"axboe@kernel.dk" <axboe@kernel.dk>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"hch@infradead.org" <hch@infradead.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"paolo.valente@linaro.org" <paolo.valente@linaro.org>
Subject: Re: Device or HBA level QD throttling creates randomness in sequetial workload
Date: Mon, 30 Jan 2017 16:30:59 +0000	[thread overview]
Message-ID: <1485793840.2712.1.camel@sandisk.com> (raw)
In-Reply-To: <e1e827ba633f780b00d070e087204d5c@mail.gmail.com>

On Mon, 2017-01-30 at 19:22 +0530, Kashyap Desai wrote:
> -   if (atomic_inc_return(&instance->fw_outstanding) >
> -           instance->host->can_queue) {
> -       atomic_dec(&instance->fw_outstanding);
> -       return SCSI_MLQUEUE_HOST_BUSY;
> -   }
> +   if (atomic_inc_return(&instance->fw_outstanding) > safe_can_queue) {
> +       is_nonrot =3D blk_queue_nonrot(scmd->device->request_queue);
> +       /* For rotational device wait for sometime to get fusion command
> from pool.
> +        * This is just to reduce proactive re-queue at mid layer which i=
s
> not
> +        * sending sorted IO in SCSI.MQ mode.
> +        */
> +       if (!is_nonrot)
> +           udelay(100);
> +   }

The SCSI core does not allow to sleep inside the queuecommand() callback
function.

Bart.=

WARNING: multiple messages have this Message-ID (diff)
From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "osandov@osandov.com" <osandov@osandov.com>,
	"kashyap.desai@broadcom.com" <kashyap.desai@broadcom.com>,
	"axboe@kernel.dk" <axboe@kernel.dk>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"hch@infradead.org" <hch@infradead.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"paolo.valente@linaro.org" <paolo.valente@linaro.org>
Subject: Re: Device or HBA level QD throttling creates randomness in sequetial workload
Date: Mon, 30 Jan 2017 16:30:59 +0000	[thread overview]
Message-ID: <1485793840.2712.1.camel@sandisk.com> (raw)
In-Reply-To: <e1e827ba633f780b00d070e087204d5c@mail.gmail.com>

On Mon, 2017-01-30 at 19:22 +0530, Kashyap Desai wrote:
> -   if (atomic_inc_return(&instance->fw_outstanding) >
> -           instance->host->can_queue) {
> -       atomic_dec(&instance->fw_outstanding);
> -       return SCSI_MLQUEUE_HOST_BUSY;
> -   }
> +   if (atomic_inc_return(&instance->fw_outstanding) > safe_can_queue) {
> +       is_nonrot = blk_queue_nonrot(scmd->device->request_queue);
> +       /* For rotational device wait for sometime to get fusion command
> from pool.
> +        * This is just to reduce proactive re-queue at mid layer which is
> not
> +        * sending sorted IO in SCSI.MQ mode.
> +        */
> +       if (!is_nonrot)
> +           udelay(100);
> +   }

The SCSI core does not allow to sleep inside the queuecommand() callback
function.

Bart.

  reply	other threads:[~2017-01-30 16:30 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-24 18:54 Device or HBA level QD throttling creates randomness in sequetial workload Kashyap Desai
2016-10-26 20:56 ` Omar Sandoval
2016-10-31 17:24 ` Jens Axboe
2016-11-01  5:40   ` Kashyap Desai
2017-01-30 13:52   ` Kashyap Desai
2017-01-30 16:30     ` Bart Van Assche [this message]
2017-01-30 16:30       ` Bart Van Assche
2017-01-30 16:32       ` Jens Axboe
2017-01-30 18:28         ` Kashyap Desai
2017-01-30 18:29           ` Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2016-10-21 12:13 Kashyap Desai
2016-10-21 21:31 ` Omar Sandoval
2016-10-22 15:04   ` Kashyap Desai
2016-10-24 13:05   ` Kashyap Desai
2016-10-24 15:41     ` Omar Sandoval
2016-10-20 10:08 Kashyap Desai
2016-10-20  9:58 Kashyap Desai

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1485793840.2712.1.camel@sandisk.com \
    --to=bart.vanassche@sandisk.com \
    --cc=axboe@kernel.dk \
    --cc=hch@infradead.org \
    --cc=kashyap.desai@broadcom.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=osandov@osandov.com \
    --cc=paolo.valente@linaro.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.