Re: [PATCH] nvme: Acknowledge completion queue on each iteration

From	Keith Busch <keith.busch@intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] nvme: Acknowledge completion queue on each iteration
Date	2017-07-18 23:30 +0200
Message-ID	<u4Ie5-7Cc-3@gated-at.bofh.it> (permalink)
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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.

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Re: [PATCH] nvme: Acknowledge completion queue on each iteration Keith Busch <keith.busch@intel.com> - 2017-07-18 16:40 +0200
  Re: [PATCH] nvme: Acknowledge completion queue on each iteration Sinan Kaya <okaya@codeaurora.org> - 2017-07-18 21:00 +0200
    Re: [PATCH] nvme: Acknowledge completion queue on each iteration Keith Busch <keith.busch@intel.com> - 2017-07-18 23:30 +0200

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