From: Jens Axboe <axboe@kernel.dk>
To: Ming Lei <ming.lei@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>,
hch@lst.de, dm-devel@redhat.com, linux-block@vger.kernel.org
Subject: Re: [PATCH v6 2/2] dm: support bio polling
Date: Wed, 9 Mar 2022 21:06:30 -0700 [thread overview]
Message-ID: <240bcfdf-a04f-069b-7574-a8a300d1d8f5@kernel.dk> (raw)
In-Reply-To: <Yil3wXO83U3zj5vj@T590>
On 3/9/22 9:00 PM, Ming Lei wrote:
> Looks improvement on 4k is small, is it caused by pcie bw limit?
> What is the IOPS when running the same t/io_uring on single optane
> directly?
Yes, see what you responded to higher up:
"which ends up being bw limited for me, because the devices aren't
linked gen4".
Some of them are, but the adapters are a bit janky and we often end up
with gen3 links and hence limited to ~3.2GB/sec per drive. But with the
bw limits even on gen4, you're roughly at about 1.5M IOPS per drive at
that point, so would expect lower percentage wise gains for 4k with
polling.
--
Jens Axboe
WARNING: multiple messages have this Message-ID (diff)
From: Jens Axboe <axboe@kernel.dk>
To: Ming Lei <ming.lei@redhat.com>
Cc: linux-block@vger.kernel.org, dm-devel@redhat.com, hch@lst.de,
Mike Snitzer <snitzer@redhat.com>
Subject: Re: [dm-devel] [PATCH v6 2/2] dm: support bio polling
Date: Wed, 9 Mar 2022 21:06:30 -0700 [thread overview]
Message-ID: <240bcfdf-a04f-069b-7574-a8a300d1d8f5@kernel.dk> (raw)
In-Reply-To: <Yil3wXO83U3zj5vj@T590>
On 3/9/22 9:00 PM, Ming Lei wrote:
> Looks improvement on 4k is small, is it caused by pcie bw limit?
> What is the IOPS when running the same t/io_uring on single optane
> directly?
Yes, see what you responded to higher up:
"which ends up being bw limited for me, because the devices aren't
linked gen4".
Some of them are, but the adapters are a bit janky and we often end up
with gen3 links and hence limited to ~3.2GB/sec per drive. But with the
bw limits even on gen4, you're roughly at about 1.5M IOPS per drive at
that point, so would expect lower percentage wise gains for 4k with
polling.
--
Jens Axboe
--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2022-03-10 4:06 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-07 18:53 [PATCH v6 0/2] block/dm: support bio polling Mike Snitzer
2022-03-07 18:53 ` [dm-devel] " Mike Snitzer
2022-03-07 18:53 ` [dm-devel] [PATCH v6 1/2] block: add ->poll_bio to block_device_operations Mike Snitzer
2022-03-07 18:53 ` Mike Snitzer
2022-03-09 1:01 ` [dm-devel] " Jens Axboe
2022-03-09 1:01 ` Jens Axboe
2022-03-07 18:53 ` [PATCH v6 2/2] dm: support bio polling Mike Snitzer
2022-03-07 18:53 ` [dm-devel] " Mike Snitzer
2022-03-09 1:02 ` Jens Axboe
2022-03-09 1:02 ` Jens Axboe
2022-03-09 1:13 ` [dm-devel] " Ming Lei
2022-03-09 1:13 ` Ming Lei
2022-03-09 16:11 ` Jens Axboe
2022-03-09 16:11 ` [dm-devel] " Jens Axboe
2022-03-10 4:00 ` Ming Lei
2022-03-10 4:00 ` [dm-devel] " Ming Lei
2022-03-10 4:06 ` Jens Axboe [this message]
2022-03-10 4:06 ` Jens Axboe
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