From: "Clément Péron" <peron.clem@gmail.com>
To: Maxime Ripard <mripard@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
"Jared D . McNeill" <jmcneill@netbsd.org>,
devicetree <devicetree@vger.kernel.org>,
Chen-Yu Tsai <wens@csie.org>, Rob Herring <robh+dt@kernel.org>,
Harald Geyer <harald@ccbib.org>,
Robin Murphy <robin.murphy@arm.com>,
arm-linux <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] arm64: dts: allwinner: a64: Drop PMU node
Date: Thu, 31 Oct 2019 20:10:16 +0100 [thread overview]
Message-ID: <CAJiuCcfcmkb_BgDcDJziUwoZXAgLN4Bh0GGZKR3NVNRpnFhBEQ@mail.gmail.com> (raw)
In-Reply-To: <20190925110844.qfm5ris7xeze44th@gilmour>
Hi,
Just a remark here but the interrupt are from 152 to 155 SPI.
But there is an offset of 32 no (remove SGI/PPI)?
This should be from 120 to 123
Regards,
Clément
On Wed, 25 Sep 2019 at 13:09, Maxime Ripard <mripard@kernel.org> wrote:
>
> On Mon, Sep 23, 2019 at 04:55:59PM -0700, Vasily Khoruzhick wrote:
> > On Mon, Sep 23, 2019 at 4:51 PM Vasily Khoruzhick <anarsoul@gmail.com> wrote:
> > >
> > > On Mon, Aug 12, 2019 at 10:39 PM Maxime Ripard
> > > <maxime.ripard@bootlin.com> wrote:
> > > >
> > > > On Mon, Aug 12, 2019 at 11:01:51AM -0700, Vasily Khoruzhick wrote:
> > > > > On Mon, Aug 12, 2019 at 1:04 AM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > > > > >
> > > > > > On Thu, Aug 08, 2019 at 12:59:07PM -0700, Vasily Khoruzhick wrote:
> > > > > > > On Thu, Aug 8, 2019 at 9:26 AM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > > > > > > >
> > > > > > > > On Wed, Aug 07, 2019 at 10:36:08AM -0700, Vasily Khoruzhick wrote:
> > > > > > > > > On Wed, Aug 7, 2019 at 4:56 AM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > > > > > > > > >
> > > > > > > > > > On Tue, Aug 06, 2019 at 07:39:26PM -0700, Vasily Khoruzhick wrote:
> > > > > > > > > > > On Tue, Aug 6, 2019 at 2:14 PM Robin Murphy <robin.murphy@arm.com> wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > On 2019-08-06 9:52 pm, Vasily Khoruzhick wrote:
> > > > > > > > > > > > > On Tue, Aug 6, 2019 at 1:19 PM Harald Geyer <harald@ccbib.org> wrote:
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> Vasily Khoruzhick writes:
> > > > > > > > > > > > >>> On Tue, Aug 6, 2019 at 7:35 AM Robin Murphy <robin.murphy@arm.com> wrote:
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>> On 06/08/2019 15:01, Vasily Khoruzhick wrote:
> > > > > > > > > > > > >>>>> Looks like PMU in A64 is broken, it generates no interrupts at all and
> > > > > > > > > > > > >>>>> as result 'perf top' shows no events.
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>> Does something like 'perf stat sleep 1' at least count cycles correctly?
> > > > > > > > > > > > >>>> It could well just be that the interrupt numbers are wrong...
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> Looks like it does, at least result looks plausible:
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> I'm using perf stat regularly (cache benchmarks) and it works fine.
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> Unfortunately I wasn't aware that perf stat is a poor test for
> > > > > > > > > > > > >> the interrupts part of the node, when I added it. So I'm not too
> > > > > > > > > > > > >> surprised I got it wrong.
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> However, it would be unfortunate if the node got removed completely,
> > > > > > > > > > > > >> because perf stat would not work anymore. Maybe we can only remove
> > > > > > > > > > > > >> the interrupts or just fix them even if the HW doesn't work?
> > > > > > > > > > > > >
> > > > > > > > > > > > > I'm not familiar with PMU driver. Is it possible to get it working
> > > > > > > > > > > > > without interrupts?
> > > > > > > > > > > >
> > > > > > > > > > > > Yup - you get a grumpy message from the driver, it will refuse sampling
> > > > > > > > > > > > events (the ones which weren't working anyway), and if you measure
> > > > > > > > > > > > anything for long enough that a counter overflows you'll get wonky
> > > > > > > > > > > > results. But for counting hardware events over relatively short periods
> > > > > > > > > > > > it'll still do the job.
> > > > > > > > > > >
> > > > > > > > > > > I tried to drop interrupts completely from the node but 'perf top' is
> > > > > > > > > > > still broken. Though now in different way: it complains "cycles: PMU
> > > > > > > > > > > Hardware doesn't support sampling/overflow-interrupts. Try 'perf
> > > > > > > > > > > stat'"
> > > > > > > > > >
> > > > > > > > > > I have no idea if that's the culprit, but what is the state of the
> > > > > > > > > > 0x09010000 register?
> > > > > > > > >
> > > > > > > > > What register is that and how do I check it?
> > > > > > > >
> > > > > > > > It's in the CPUX Configuration block, and the bits are labelled as CPU
> > > > > > > > Debug Reset.
> > > > > > > >
> > > > > > > > And if you have busybox, you can use devmem.
> > > > > > >
> > > > > > > CPUX configuration block is at 0x01700000 according to A64 user
> > > > > > > manual, and particular register you're interested in is at 0x01700080,
> > > > > > > its value is 0x1110110F.
> > > > > > >
> > > > > > > Bits 16-19 are not defined in user manual and are not set.
> > > > > >
> > > > > > Sorry, I somehow thought this was for the H6...
> > > > > >
> > > > > > I don't have any idea then :/
> > > > >
> > > > > OK, so what should we do? 'perf top'/'perf record' work fine if PMU
> > > > > node is dropped, but they don't work if PMU node is present (even with
> > > > > interrupts dropped). I'd prefer to have 'perf top' and 'perf record'
> > > > > working instead of 'perf stat'
> > > >
> > > > Well, it doesn't work so we should just remove the node, and if
> > > > someone wants it back, they should figure it out.
> > >
> > > Hey Maxime,
> > >
> > > So can you merge this patch?
> >
> > Added new Maxime's email to CC
>
> Queued as a fix for 5.4, thanks!
> Maxime
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next prev parent reply other threads:[~2019-10-31 19:10 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-06 14:01 [PATCH] arm64: dts: allwinner: a64: Drop PMU node Vasily Khoruzhick
2019-08-06 14:35 ` Robin Murphy
2019-08-06 14:45 ` Vasily Khoruzhick
2019-08-06 20:19 ` Harald Geyer
2019-08-06 20:52 ` Vasily Khoruzhick
2019-08-06 21:14 ` Robin Murphy
2019-08-07 2:39 ` Vasily Khoruzhick
2019-08-07 11:56 ` Maxime Ripard
2019-08-07 17:36 ` Vasily Khoruzhick
2019-08-08 16:26 ` Maxime Ripard
2019-08-08 19:59 ` Vasily Khoruzhick
2019-08-12 8:04 ` Maxime Ripard
2019-08-12 18:01 ` Vasily Khoruzhick
2019-08-12 18:22 ` Harald Geyer
2019-08-13 5:39 ` Maxime Ripard
2019-09-23 23:51 ` Vasily Khoruzhick
2019-09-23 23:55 ` Vasily Khoruzhick
2019-09-25 11:08 ` Maxime Ripard
2019-10-31 19:10 ` Clément Péron [this message]
2019-10-31 20:35 ` Vasily Khoruzhick
2019-11-01 11:30 ` Clément Péron
2019-11-01 15:47 ` Andre Przywara
2019-11-11 1:43 ` André Przywara
2019-08-07 11:59 ` Robin Murphy
2019-08-07 11:12 ` Mark Rutland
2019-08-06 19:10 ` Emmanuel Vadot
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