From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH 4/4] nvme-core: support traffic based keep-alive based on controller support
Date: Fri, 19 Oct 2018 08:00:49 +0200 [thread overview]
Message-ID: <20181019060049.GA27902@lst.de> (raw)
In-Reply-To: <2e1cba3c-a391-8c45-5987-0ba5317a6a19@grimberg.me>
On Thu, Oct 18, 2018@05:38:29PM -0700, Sagi Grimberg wrote:
>
>>> + nvme_req(req)->ctrl->comp_seen = true;
>>
>> shouldn't we only do this for controllers with keep a live support?
>
> What is the harm setting it anyways? Would it be better to condition it
> on keep alive support instead?
This writes to a cache line in the controller on every I/O completion.
And while it isn't an atomic it isn't exactly going to help scalability,
so I'd rather have a branch before it, which will be predicted not taken
for controllers that don't have the feature (aka at least every PCIe
controller on the planet)
next prev parent reply other threads:[~2018-10-19 6:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-28 1:15 [PATCH 0/4] traffic based keep alive support (TP 4024) Sagi Grimberg
2018-09-28 1:15 ` [PATCH 1/4] nvme: introduce ctrl attributes enumeration Sagi Grimberg
2018-09-28 1:15 ` [PATCH 2/4] nvmet: support for traffic based keep-alive Sagi Grimberg
2018-09-28 1:15 ` [PATCH 3/4] nvme-core: cache controller attributes Sagi Grimberg
2018-09-28 1:15 ` [PATCH 4/4] nvme-core: support traffic based keep-alive based on controller support Sagi Grimberg
2018-10-17 7:05 ` Christoph Hellwig
2018-10-19 0:38 ` Sagi Grimberg
2018-10-19 6:00 ` Christoph Hellwig [this message]
2018-10-19 6:30 ` Sagi Grimberg
2018-10-16 1:07 ` [PATCH 0/4] traffic based keep alive support (TP 4024) Sagi Grimberg
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