From: Jens Axboe <axboe@kernel.dk>
To: sbates@raithlin.com
Cc: linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
Damien.LeMoal@wdc.com, osandov@osandov.com, sagi@grimberg.me
Subject: Re: [PATCH v2 2/2] blk-mq: Add a polling specific stats function
Date: Wed, 5 Apr 2017 12:14:33 -0600 [thread overview]
Message-ID: <370c8854-1735-b0e7-089f-4b04068ca4f1@kernel.dk> (raw)
In-Reply-To: <1491413957-30885-3-git-send-email-sbates@raithlin.com>
On 04/05/2017 11:39 AM, sbates@raithlin.com wrote:
> @@ -42,6 +42,33 @@ static LIST_HEAD(all_q_list);
> static void blk_mq_poll_stats_start(struct request_queue *q);
> static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
>
> +static int blk_mq_poll_stats_bkt(const struct request *rq)
> +{
> + int dir, bytes;
> +
> + dir = blk_stat_rq_ddir(rq);
> + bytes = blk_rq_bytes(rq);
> +
> + if (bytes <= 512)
> + return dir;
> + else if (bytes <= 4096)
> + return dir + 2;
> + else if (bytes <= 8192)
> + return dir + 4;
> + else if (bytes <= 16384)
> + return dir + 6;
> + else if (bytes <= 32768)
> + return dir + 8;
> + else if (bytes <= 65536)
> + return dir + 10;
> + else
> + return dir + 12;
Why not just have 8 buckets, and make it:
bucket = ddir + ilog2(bytes) - 9;
and cap it at MAX_BUCKET (8) and put all those above into the top
bucket.
--
Jens Axboe
next prev parent reply other threads:[~2017-04-05 18:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 17:39 [PATCH v2 0/2] blk-stat: Add ability to not bucket IO; improve IO polling sbates
2017-04-05 17:39 ` [PATCH v2 1/2] blk-stat: convert blk-stat bucket callback to signed sbates
2017-04-05 17:39 ` [PATCH v2 2/2] blk-mq: Add a polling specific stats function sbates
2017-04-05 18:14 ` Jens Axboe [this message]
2017-04-07 12:11 ` Stephen Bates
2017-04-07 14:01 ` Jens Axboe
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