From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: Marta Rybczynska <mrybczyn-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
Cc: linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
keith.busch-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
axboe-b10kYP2dOMg@public.gmane.org,
hch-jcswGhMUV9g@public.gmane.org,
sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org,
Samuel Jones
<samuel.jones-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
Subject: Re: [PATCH RFC] nvme-rdma: support devices with queue size < 32
Date: Thu, 23 Mar 2017 15:00:42 +0100 [thread overview]
Message-ID: <20170323140042.GA30536@lst.de> (raw)
In-Reply-To: <1315914765.312051621.1490259849534.JavaMail.zimbra-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
On Thu, Mar 23, 2017 at 10:04:09AM +0100, Marta Rybczynska wrote:
> In the case of small NVMe-oF queue size (<32) we may enter
> a deadlock caused by the fact that the IB completions aren't sent
> waiting for 32 and the send queue will fill up.
>
> The error is seen as (using mlx5):
> [ 2048.693355] mlx5_0:mlx5_ib_post_send:3765:(pid 7273):
> [ 2048.693360] nvme nvme1: nvme_rdma_post_send failed with error code -12
>
> The patch doesn't change the behaviour for remote devices with
> larger queues.
Thanks, this looks useful. But wouldn't it be better to do something
like queue_size divided by 2 or 4 to get a better refill latency?
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next prev parent reply other threads:[~2017-03-23 14:00 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-23 9:04 [PATCH RFC] nvme-rdma: support devices with queue size < 32 Marta Rybczynska
[not found] ` <1315914765.312051621.1490259849534.JavaMail.zimbra-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
2017-03-23 14:00 ` Christoph Hellwig [this message]
[not found] ` <20170323140042.GA30536-jcswGhMUV9g@public.gmane.org>
2017-03-23 14:36 ` Marta Rybczynska
[not found] ` <277345557.313693033.1490279818647.JavaMail.zimbra-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
2017-03-28 11:09 ` Sagi Grimberg
[not found] ` <4951fac6-662f-29a6-5ba5-38d37a2c2dca-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
2017-03-28 11:20 ` Marta Rybczynska
[not found] ` <1180136633.325075447.1490700022740.JavaMail.zimbra-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
2017-03-28 11:30 ` Sagi Grimberg
[not found] ` <8dc0414f-be90-ee30-0f66-8cee26c4c2aa-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
2017-03-29 9:36 ` Marta Rybczynska
2017-03-29 13:29 ` Jason Gunthorpe
[not found] ` <20170329132918.GA32072-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-29 15:47 ` Sagi Grimberg
[not found] ` <406682b9-d7ca-4718-5830-7940d2822bc0-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
2017-03-29 16:27 ` Jason Gunthorpe
[not found] ` <20170329162751.GA7113-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-29 16:39 ` Sagi Grimberg
[not found] ` <80770042-743e-a271-c636-f72099f9ac56-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
2017-03-29 16:44 ` Doug Ledford
[not found] ` <9eb08168-18a6-a176-01df-b68b6a225963-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-03-29 16:47 ` Doug Ledford
[not found] ` <3505b835-d0ba-70cb-dfe8-1265fc2bbb83-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-03-29 16:59 ` Sagi Grimberg
[not found] ` <2ba93b5b-ad36-5533-36e2-9db2e3198c19-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
2017-03-29 22:19 ` Jason Gunthorpe
2017-03-30 14:23 ` Marta Rybczynska
[not found] ` <1121115847.336382032.1490883808617.JavaMail.zimbra-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
2017-04-06 12:29 ` Marta Rybczynska
[not found] ` <1224897571.353404199.1491481743295.JavaMail.zimbra-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
2017-04-06 13:02 ` Leon Romanovsky
[not found] ` <20170406130207.GI2269-U/DQcQFIOTAAJjI8aNfphQ@public.gmane.org>
2017-04-07 13:31 ` Marta Rybczynska
[not found] ` <1917497781.360337179.1491571916242.JavaMail.zimbra-FNhOzJFKnXGHXe+LvDLADg@public.gmane.org>
2017-04-09 12:31 ` Sagi Grimberg
[not found] ` <c7e56394-feb3-282b-0eec-166ef0d8b13c-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
2017-04-10 11:29 ` Marta Rybczynska
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