From: Keith Busch <keith.busch@intel.com>
To: Sinan Kaya <okaya@codeaurora.org>
Cc: linux-nvme@lists.infradead.org, timur@codeaurora.org,
linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, Jens Axboe <axboe@fb.com>,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nvme: Acknowledge completion queue on each iteration
Date: Tue, 18 Jul 2017 17:26:32 -0400 [thread overview]
Message-ID: <20170718212631.GB1202@localhost.localdomain> (raw)
In-Reply-To: <dada875c-ed69-0126-8e83-78a564e6b4bd@codeaurora.org>
On Tue, Jul 18, 2017 at 02:52:26PM -0400, Sinan Kaya wrote:
> On 7/18/2017 10:36 AM, Keith Busch wrote:
>
> I do see that the NVMe driver is creating a completion interrupt on
> each CPU core for the completions. No problems with that.
>
> However, I don't think you can guarantee that there will always be a single
> CPU core targeting one submission queue especially with asynchronous IO.
>
> Lock contention counters from CONFIG_LOCK_STAT are pointing to nvmeq->lock
> in my FIO tests.
>
> Did I miss something?
I think that must mean your machine has many more CPUs than your nvme
controller has IO queues.
next prev parent reply other threads:[~2017-07-18 21:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-17 22:36 [PATCH] nvme: Acknowledge completion queue on each iteration Sinan Kaya
2017-07-17 22:45 ` Keith Busch
2017-07-17 22:46 ` Sinan Kaya
2017-07-17 22:56 ` Keith Busch
2017-07-17 23:07 ` okaya
2017-07-18 14:36 ` Keith Busch
2017-07-18 18:52 ` Sinan Kaya
2017-07-18 21:26 ` Keith Busch [this message]
2017-07-19 9:20 ` Sagi Grimberg
2017-07-19 10:37 ` Sinan Kaya
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