From: Ilya Dikariev <dikarill@b-tu.de>
To: Marc Zyngier <maz@kernel.org>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
"Daniel Lezcano" <daniel.lezcano@linaro.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Samuel Holland" <samuel@sholland.org>,
"Chen-Yu Tsai" <wens@csie.org>,
"Jernej Škrabec" <jernej.skrabec@gmail.com>,
linux-sunxi@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drivers/clocksource/arm_arch_timer: Tighten Allwinner arch timer workaround
Date: Thu, 10 Nov 2022 12:10:01 +0100 [thread overview]
Message-ID: <20221110121001.214a851d@rosh> (raw)
In-Reply-To: <87k043us6e.wl-maz@kernel.org>
El Thu, 10 Nov 2022 08:31:21 +0000
Marc Zyngier <maz@kernel.org> escribió:
MZ> >
MZ> > As we know, the Allwinner A64 SoC has a buggy RCU time unit. The
MZ>
MZ> What is RCU?
I think I called it wrong. Anyway I mean the HR timer of A64.
MZ>
MZ> > workaround named UNKNOWN1 was not sufficient to cover some more buggy
MZ> > bunches of this SoC. This workaround diminish the mask to 8 bits instead
MZ> > of 9.
MZ> >
MZ> > An example run of timer test tool https://github.com/smaeul/timer-tools
MZ> > on PinePhone device (owns the A64 SoC) gives following result on a non
MZ> > patched kernel (cut off):
MZ> >
MZ> > Running parallel counter test...
MZ> > 0: Failed after 5507 reads (0.003578 s)
MZ> > 0: 0x0000000c8272cbf1 -> 0x0000000c8272ccff -> 0x0000000c8272cc0e ( 0.011 ms)
[......]
MZ> > After the proposed patch applied the test runs
MZ> > correctly (~2 hours of testing with a tool above without fails)
MZ>
MZ> 2 hours seems like an incredibly small amount of time given that the
MZ> existing workaround was believed to be correct. Run it continuously
MZ> for a couple of weeks on several different machines with varying
MZ> workloads and less us know the outcome.
The only A64 machine I own is the Pinephone. First time I did this patch
~9 month ago (on behalf os Samuel). Before it the system suffered hangs
every 15-20 minutes and backward time jumps ~1 time a day.
Since applying of this patch none of above occurred.
To be honest, I never did long tests (weeks). I will put the device
on a probe for some weeks and let you know then.
Best regards,
Ilya
--
запрягай медленно,
едь быстро!
WARNING: multiple messages have this Message-ID (diff)
From: Ilya Dikariev <dikarill@b-tu.de>
To: Marc Zyngier <maz@kernel.org>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
"Daniel Lezcano" <daniel.lezcano@linaro.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Samuel Holland" <samuel@sholland.org>,
"Chen-Yu Tsai" <wens@csie.org>,
"Jernej Škrabec" <jernej.skrabec@gmail.com>,
linux-sunxi@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drivers/clocksource/arm_arch_timer: Tighten Allwinner arch timer workaround
Date: Thu, 10 Nov 2022 12:10:01 +0100 [thread overview]
Message-ID: <20221110121001.214a851d@rosh> (raw)
In-Reply-To: <87k043us6e.wl-maz@kernel.org>
El Thu, 10 Nov 2022 08:31:21 +0000
Marc Zyngier <maz@kernel.org> escribió:
MZ> >
MZ> > As we know, the Allwinner A64 SoC has a buggy RCU time unit. The
MZ>
MZ> What is RCU?
I think I called it wrong. Anyway I mean the HR timer of A64.
MZ>
MZ> > workaround named UNKNOWN1 was not sufficient to cover some more buggy
MZ> > bunches of this SoC. This workaround diminish the mask to 8 bits instead
MZ> > of 9.
MZ> >
MZ> > An example run of timer test tool https://github.com/smaeul/timer-tools
MZ> > on PinePhone device (owns the A64 SoC) gives following result on a non
MZ> > patched kernel (cut off):
MZ> >
MZ> > Running parallel counter test...
MZ> > 0: Failed after 5507 reads (0.003578 s)
MZ> > 0: 0x0000000c8272cbf1 -> 0x0000000c8272ccff -> 0x0000000c8272cc0e ( 0.011 ms)
[......]
MZ> > After the proposed patch applied the test runs
MZ> > correctly (~2 hours of testing with a tool above without fails)
MZ>
MZ> 2 hours seems like an incredibly small amount of time given that the
MZ> existing workaround was believed to be correct. Run it continuously
MZ> for a couple of weeks on several different machines with varying
MZ> workloads and less us know the outcome.
The only A64 machine I own is the Pinephone. First time I did this patch
~9 month ago (on behalf os Samuel). Before it the system suffered hangs
every 15-20 minutes and backward time jumps ~1 time a day.
Since applying of this patch none of above occurred.
To be honest, I never did long tests (weeks). I will put the device
on a probe for some weeks and let you know then.
Best regards,
Ilya
--
запрягай медленно,
едь быстро!
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next prev parent reply other threads:[~2022-11-10 11:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-09 21:10 [PATCH] drivers/clocksource/arm_arch_timer: Tighten Allwinner arch timer workaround Ilya Dikariev
2022-11-09 21:10 ` Ilya Dikariev
2022-11-10 8:31 ` Marc Zyngier
2022-11-10 8:31 ` Marc Zyngier
2022-11-10 11:10 ` Ilya Dikariev [this message]
2022-11-10 11:10 ` Ilya Dikariev
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