From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <keith.busch@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>, Scott Bauer <sbauer@eng.utah.edu>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH 3/3] block: Polling completion performance optimization
Date: Fri, 29 Dec 2017 10:50:21 +0100 [thread overview]
Message-ID: <20171229095021.GD24043@lst.de> (raw)
In-Reply-To: <20171221213400.GB2975@localhost.localdomain>
On Thu, Dec 21, 2017 at 02:34:00PM -0700, Keith Busch wrote:
> It would be nice, but the driver doesn't know a request's completion
> is going to be a polled.
We can trivially set a REQ_POLL bit. In fact my initial patch kit had
those on the insitence of Jens, but then I removed it because we had
no users for it.
> Even if it did, we don't have a spec defined
> way to tell the controller not to send an interrupt with this command's
> compeletion, which would be negated anyway if any interrupt driven IO
> is mixed in the same queue.
Time to add such a flag to the spec then..
> We could possibly create a special queue
> with interrupts disabled for this purpose if we can pass the HIPRI hint
> through the request.
Eww. That means we double our resource usage both in the host and
the device, which isn't going to be pretty.
WARNING: multiple messages have this Message-ID (diff)
From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH 3/3] block: Polling completion performance optimization
Date: Fri, 29 Dec 2017 10:50:21 +0100 [thread overview]
Message-ID: <20171229095021.GD24043@lst.de> (raw)
In-Reply-To: <20171221213400.GB2975@localhost.localdomain>
On Thu, Dec 21, 2017@02:34:00PM -0700, Keith Busch wrote:
> It would be nice, but the driver doesn't know a request's completion
> is going to be a polled.
We can trivially set a REQ_POLL bit. In fact my initial patch kit had
those on the insitence of Jens, but then I removed it because we had
no users for it.
> Even if it did, we don't have a spec defined
> way to tell the controller not to send an interrupt with this command's
> compeletion, which would be negated anyway if any interrupt driven IO
> is mixed in the same queue.
Time to add such a flag to the spec then..
> We could possibly create a special queue
> with interrupts disabled for this purpose if we can pass the HIPRI hint
> through the request.
Eww. That means we double our resource usage both in the host and
the device, which isn't going to be pretty.
next prev parent reply other threads:[~2017-12-29 9:50 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-21 20:46 [PATCH 0/3] Performance enhancements Keith Busch
2017-12-21 20:46 ` Keith Busch
2017-12-21 20:46 ` [PATCH 1/3] nvme/pci: Start request after doorbell ring Keith Busch
2017-12-21 20:46 ` Keith Busch
2017-12-21 20:49 ` Jens Axboe
2017-12-21 20:49 ` Jens Axboe
2017-12-21 20:53 ` Jens Axboe
2017-12-21 20:53 ` Jens Axboe
2017-12-21 21:02 ` Keith Busch
2017-12-21 21:02 ` Keith Busch
2017-12-21 21:01 ` Jens Axboe
2017-12-21 21:01 ` Jens Axboe
2018-01-03 20:21 ` Keith Busch
2018-01-03 20:21 ` Keith Busch
2018-01-23 0:16 ` Keith Busch
2018-01-23 0:16 ` Keith Busch
2017-12-25 10:12 ` Sagi Grimberg
2017-12-25 10:12 ` Sagi Grimberg
2017-12-29 9:44 ` Christoph Hellwig
2017-12-29 9:44 ` Christoph Hellwig
2017-12-25 10:11 ` Sagi Grimberg
2017-12-25 10:11 ` Sagi Grimberg
2017-12-26 20:35 ` Keith Busch
2017-12-26 20:35 ` Keith Busch
2017-12-27 9:02 ` Sagi Grimberg
2017-12-27 9:02 ` Sagi Grimberg
2017-12-29 9:44 ` Christoph Hellwig
2017-12-29 9:44 ` Christoph Hellwig
2017-12-21 20:46 ` [PATCH 2/3] nvme/pci: Remove cq_vector check in IO path Keith Busch
2017-12-21 20:46 ` Keith Busch
2017-12-21 20:54 ` Jens Axboe
2017-12-21 20:54 ` Jens Axboe
2017-12-25 10:10 ` Sagi Grimberg
2017-12-25 10:10 ` Sagi Grimberg
2017-12-27 21:01 ` Sagi Grimberg
2017-12-27 21:01 ` Sagi Grimberg
2017-12-29 9:48 ` Christoph Hellwig
2017-12-29 9:48 ` Christoph Hellwig
2017-12-29 15:39 ` Keith Busch
2017-12-29 15:39 ` Keith Busch
2017-12-31 12:30 ` Sagi Grimberg
2017-12-31 12:30 ` Sagi Grimberg
2018-01-02 16:50 ` Keith Busch
2018-01-02 16:50 ` Keith Busch
2017-12-21 20:46 ` [PATCH 3/3] block: Polling completion performance optimization Keith Busch
2017-12-21 20:46 ` Keith Busch
2017-12-21 20:56 ` Scott Bauer
2017-12-21 20:56 ` Scott Bauer
2017-12-21 21:00 ` Jens Axboe
2017-12-21 21:00 ` Jens Axboe
2017-12-21 21:34 ` Keith Busch
2017-12-21 21:34 ` Keith Busch
2017-12-21 22:17 ` Jens Axboe
2017-12-21 22:17 ` Jens Axboe
2017-12-21 23:10 ` Keith Busch
2017-12-21 23:10 ` Keith Busch
2017-12-22 15:40 ` Jens Axboe
2017-12-22 15:40 ` Jens Axboe
2017-12-29 9:50 ` Christoph Hellwig [this message]
2017-12-29 9:50 ` Christoph Hellwig
2017-12-29 15:51 ` Keith Busch
2017-12-29 15:51 ` Keith Busch
2017-12-31 12:48 ` Sagi Grimberg
2017-12-31 12:48 ` Sagi Grimberg
2017-12-21 20:57 ` Jens Axboe
2017-12-21 20:57 ` Jens Axboe
2017-12-29 9:51 ` Christoph Hellwig
2017-12-29 9:51 ` Christoph Hellwig
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