Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 03 Aug 2020 14:24:39 +0100 | From | Marc Zyngier <> | Subject | Re: [RFC PATCH] arm64: defconfig: Disable fine-grained task level IRQ time accounting |
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On 2020-08-03 12:48, Valentin Schneider wrote: > On 03/08/20 12:38, Vladimir Oltean wrote: >> On Mon, Aug 03, 2020 at 10:51:32AM +0100, Robin Murphy wrote: >>> >>> Having glanced across another thread that mentions IRQ accounting >>> recently[1], I wonder if the underlying bug here might have something >>> do to >>> with the stuff that Marc's trying to clean up. >>> >>> Robin. >>> >>> [1] >>> https://lore.kernel.org/linux-arm-kernel/20200624195811.435857-16-maz@kernel.org/ >> >> Thanks Robin. I've applied Marc's "[PATCH v2 00/17] arm/arm64: Turning >> IPIs into normal interrupts" series and the LS1028A I'm debugging >> hangs >> in absolutely the same way. >> > > I'm not too surprised by that, wrt accounting this mostly changes where > the > stores go to and barely shuffles when they happen (slightly earlier on > the > IPI handling path).
Indeed. This series is just a "let's make things be the way they should be", and isn't really fixing any bug. It actually may introduce a couple...
> FWIW I've had 'stress-ng --hrtimers 1' running on my Juno and eMAG for > ~15 > minutes and haven't had a splat yet.
I've started a couple of VMs with that workload too. 400K irq/s on an 8 vcpu guest, nothing to report so far.
But removing IRQ_TIME_ACCOUNTING from defconfig is a resounding "no way!". It looks like we have a bug, and it should be squashed, not glanced over.
M. -- Jazz is not dead. It just smells funny...
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