From: Mark Rutland <mark.rutland@arm.com>
To: Will Deacon <will.deacon@arm.com>
Cc: Yabin Cui <yabinc@google.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm/perf: Fix pmu percpu irq handling at hotplug.
Date: Tue, 30 Aug 2016 18:32:25 +0100 [thread overview]
Message-ID: <20160830173224.GN1223@leverpostej> (raw)
In-Reply-To: <20160826094800.GD13554@arm.com>
Hi,
On Fri, Aug 26, 2016 at 10:48:00AM +0100, Will Deacon wrote:
> On Fri, Aug 19, 2016 at 03:25:14PM +0100, Mark Rutland wrote:
> > On Thu, Aug 18, 2016 at 01:24:38PM -0700, Yabin Cui wrote:
> > > If the cpu pmu is using a percpu irq:
> > >
> > > 1. When a cpu is down, we should disable pmu irq on
> > > that cpu. Otherwise, if the cpu is still down when
> > > the last perf event is released, the pmu irq can't
> > > be freed. Because the irq is still enabled on the
> > > offlined cpu. And following perf_event_open()
> > > syscalls will fail.
> > >
> > > 2. When a cpu is up, we should enable pmu irq on
> > > that cpu. Otherwise, profiling tools can't sample
> > > events on the cpu before all perf events are
> > > released, because pmu irq is disabled on that cpu.
[...]
> > Rather than adding more moving parts to the IRQ manipulation logic, I'd
> > rather we rework the IRQ manipulation logic to:
> >
> > * At probe time, request all the interrupts. If we can't, bail out and
> > fail the probe.
> >
> > * Upon hotplug in (and at probe time), configure the affinity and
> > enable the relevant interrupt(s).
> >
> > * Upon hotplug out, disable the relevant interrupt.
> > I'm taking a look at doing the above, but I don't yet have a patch.
>
> Any update on this? I'd quite like to do *something* to fix the issues
> reported here.
Apologies for the delay.
I've been away from my development hardware for the last week, so I
ahven't fought with this for a few days.
Given it's requiring that I practically rewrite of_pmu_irq_cfg and
friends, it may be better to take Yabin's patch for the timebeing if you
want a quick fix for this particular issue.
Thanks,
Mark.
next prev parent reply other threads:[~2016-08-30 17:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CALJ9ZPMixfGKspzaz+vTGQZG4EaQB5Futss-aC-Z+8oztVX9Nw@mail.gmail.com>
2016-08-19 14:25 ` [PATCH] arm/perf: Fix pmu percpu irq handling at hotplug Mark Rutland
2016-08-26 9:48 ` Will Deacon
2016-08-30 17:32 ` Mark Rutland [this message]
2016-08-31 14:41 ` Will Deacon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160830173224.GN1223@leverpostej \
--to=mark.rutland@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=will.deacon@arm.com \
--cc=yabinc@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).