From: Lukas Wunner <lukas@wunner.de>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Alex G <mr.nuke.me@gmail.com>,
bhelgaas@google.com, helgaas@kernel.org,
linux-pci@vger.kernel.org, austin_bolen@dell.com,
alex_gagniuc@dellteam.com, keith.busch@intel.com,
Shyam_Iyer@Dell.com, okaya@kernel.org,
torvalds@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI/LINK: Account for BW notification in vector calculation
Date: Tue, 23 Apr 2019 17:49:20 +0200 [thread overview]
Message-ID: <20190423154920.uytvswrxx7plv3dh@wunner.de> (raw)
In-Reply-To: <20190423093408.16b07efc@x1.home>
On Tue, Apr 23, 2019 at 09:34:08AM -0600, Alex Williamson wrote:
> On Tue, 23 Apr 2019 09:33:53 -0500 Alex G <mr.nuke.me@gmail.com> wrote:
> > 0.5W savings on a 100+W GPU? I agree it's meaningless.
>
> Evidence? Regardless, I don't have control of the driver that's making
> these changes, but the claim seems unfounded and irrelevant.
On laptops, 0.5 W can result in noticeably longer battery life.
> I can see why we might want to
> be notified of degraded links due to signal issues, but what I'm
> reporting is that there are also entirely normal and benign reasons
> that a link might be reduced, we can't seem to tell the difference
> between a fault and this normal dynamic scaling, and the assumption of
> a fault is spamming dmesg. So, I don't think what we have here is well
> cooked. Do drivers have a mechanism to opt-out of this error
> reporting?
Is dmesg spammed even if no driver is bound to a GPU? If so, that would
suggest a solution that's not dependent on drivers. E.g., the
bw_notification port service could avoid reports for devices matching
PCI_BASE_CLASS_DISPLAY. (It could also avoid binding to ports whose
children include such a device, but the child may be hot-pluggable
and thus appear only after the port is bound.) Then we'd still get
a notification on boot about degraded link speed, but not continuous
messages.
Thanks,
Lukas
next prev parent reply other threads:[~2019-04-23 15:49 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-22 22:43 Alex Williamson
2019-04-23 0:05 ` Alex G
2019-04-23 0:33 ` Alex Williamson
2019-04-23 14:33 ` Alex G
2019-04-23 15:34 ` Alex Williamson
2019-04-23 15:49 ` Lukas Wunner [this message]
2019-04-23 16:03 ` Alex G
2019-04-23 16:22 ` Alex Williamson
2019-04-23 16:27 ` Alex G
2019-04-23 16:37 ` Alex Williamson
2019-04-23 17:10 ` Bjorn Helgaas
2019-04-23 17:53 ` Alex G
2019-04-23 18:38 ` Alex Williamson
2019-04-23 17:59 ` Alex G
2019-05-01 20:30 ` Bjorn Helgaas
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