Messages in this thread | | | Date | Fri, 28 Apr 2023 09:30:16 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: Unfair qspinlocks on ARM64 without LSE atomics => 3ms delay in interrupt handling |
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On 2023-04-27 15:45:09 [+0200], Kurt Kanzenbach wrote: > > Are we aware of other concrete case where it bites? Even with just > > "normal" contented spin_lock usage? > > Well, some years ago I've observed a similar problem with ARM64 > spinlocks, cpu_relax() and retry loops (in the futex code). It also > generated latency spikes up to 2-3ms. Back then, it was easily > reproducible using stress-ng --ptrace 4.
That was fixed by https://patchwork.kernel.org/project/linux-arm-kernel/patch/1399528508-2806-1-git-send-email-arjun.kv@samsung.com
if my memory serves me well.
> Thanks, > Kurt
Sebastian
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