From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: Andy Lutomirski <luto@kernel.org>
Cc: "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Keith Busch <keith.busch@intel.com>, Jens Axboe <axboe@fb.com>,
linux-nvme@lists.infradead.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
J Freyensee <james_p_freyensee@linux.intel.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: Should drivers like nvme let userspace control their latency via dev_pm_qos?
Date: Fri, 16 Sep 2016 16:54:31 +0100 [thread overview]
Message-ID: <20160916165431.1f2e6df5@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <CALCETrUsgA2H=TuwZMuwW2XpXZ7KPrEYu6xckmTbhU8oZwr6Nw@mail.gmail.com>
On Fri, 16 Sep 2016 08:26:03 -0700
Andy Lutomirski <luto@kernel.org> wrote:
> I'm adding power management to the nvme driver, and I'm exposing
> exactly one knob via sysfs: the maximum permissible latency. This
> isn't a power domain issue, and it has no dependencies -- it's
> literally just the maximum latency that the driver may impose on I/O
> for power saving purposes.
Why is this in the driver. Surely the latency is a property of the
request queue and the requests being made. Now it may well be that its
implement as min(list-of-queues) but a device sysfs node seems a strange
place to stick it.
Alan
next prev parent reply other threads:[~2016-09-16 15:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-16 15:26 Andy Lutomirski
2016-09-16 15:54 ` One Thousand Gnomes [this message]
2016-09-16 16:20 ` Andy Lutomirski
2016-09-23 1:26 ` Rafael J. Wysocki
2016-09-23 1:40 ` Andy Lutomirski
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