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From: Keith Busch <kbusch@kernel.org>
To: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Cc: Mark Ruijter <MRuijter@onestopsystems.com>,
	Hannes Reinecke <hare@suse.com>, "hch@lst.de" <hch@lst.de>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
	"sagi@grimberg.me" <sagi@grimberg.me>
Subject: Re: [PATCH] nvmet: introduce use_vfs ns-attr
Date: Mon, 28 Oct 2019 17:01:33 +0900
Message-ID: <20191028080133.GA1718@redsun51.ssa.fujisawa.hgst.com> (raw)
In-Reply-To: <BYAPR04MB57491F5ED34EEE047D86C2D186660@BYAPR04MB5749.namprd04.prod.outlook.com>

On Mon, Oct 28, 2019 at 07:32:45AM +0000, Chaitanya Kulkarni wrote:
> diff --git a/drivers/nvme/target/io-cmd-bdev.c 
> b/drivers/nvme/target/io-cmd-bdev.c
> index ed1a8d0..07e4f8c 100644
> --- a/drivers/nvme/target/io-cmd-bdev.c
> +++ b/drivers/nvme/target/io-cmd-bdev.c
> @@ -204,9 +204,9 @@ static void nvmet_bdev_execute_rw(struct nvmet_req *req)
>                  sector += sg->length >> 9;
>                  sg_cnt--;
>          }
> -       blk_finish_plug(&plug);
> 
>          submit_bio(bio);
> +       blk_finish_plug(&plug);
>   }
> 
>   static void nvmet_bdev_execute_flush(struct nvmet_req *req)
> 
>    write: IOPS=123k, BW=479MiB/s (502MB/s)(14.0GiB/30009msec)
>    write: IOPS=123k, BW=480MiB/s (504MB/s)(14.1GiB/30002msec)
>      slat (usec): min=8, max=8778, avg=13.29, stdev= 5.70
>      slat (usec): min=8, max=315, avg=13.28, stdev= 3.38
>      clat (usec): min=44, max=9790, avg=246.21, stdev=167.10
>      clat (usec): min=27, max=10883, avg=245.59, stdev=164.19
> 
> 
> Still need to look into the code to make sure above change make sense.

The block plug code change definitely makes sense. I don't think there's a
better place to plug without a more invasive change, so let's use this. I
don't immediately understand why it measures this much of a difference for
this workload, though.

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  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-23 20:17 Chaitanya Kulkarni
2019-10-24  2:00 ` Keith Busch
2019-10-24 11:30   ` Mark Ruijter
2019-10-25  4:05     ` Keith Busch
2019-10-25  4:26       ` Keith Busch
2019-10-25  8:44         ` Mark Ruijter
2019-10-26  1:06           ` Keith Busch
2019-10-27 15:03           ` hch
2019-10-27 16:06             ` Mark Ruijter
2019-10-28  0:55             ` Keith Busch
2019-10-28  7:26               ` Chaitanya Kulkarni
2019-10-28  7:32               ` Chaitanya Kulkarni
2019-10-28  7:35                 ` hch
2019-10-28  7:38                   ` Chaitanya Kulkarni
2019-10-28  7:43                     ` hch
2019-10-28  8:04                       ` Chaitanya Kulkarni
2019-10-28  8:01                 ` Keith Busch [this message]
2019-10-28  8:41                   ` Mark Ruijter
2019-10-25  3:29   ` Chaitanya Kulkarni

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