Messages in this thread | | | Date | Tue, 11 Jan 2022 11:05:06 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH] arm64: Make CONFIG_ARM64_PSEUDO_NMI macro wrap all the pseudo-NMI code |
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On Tue, Jan 11, 2022 at 04:52:32PM +0800, He Ying wrote: > 在 2022/1/10 19:26, Mark Rutland 写道: > > On Mon, Jan 10, 2022 at 11:00:43AM +0800, He Ying wrote: > > > 在 2022/1/7 21:19, Mark Rutland 写道: > > > > On Fri, Jan 07, 2022 at 03:55:36AM -0500, He Ying wrote:
> > Due to the large numbers, I suspect this must be due to a specific fast-path, > > and it's possible that this is due to secondary factors (e.g. alignment of > > code) rather than the pseudo-NMK code itself. > > > > We need to narrow down *where* time is being spent. Since it appears that this > > is related to the local IRQ state management, it isn't likely that we can > > determine that reliably with the PMU. Given that, I think the first step is to > > reproduce the result elsewhere, for which we will need some plublicly available > > test-case. > > As said before, I asked our collegues how they did the ARP test. In one word, > a very small performance regression may bring the big change to the test > result. > > I feel very sorry for missing this important information. So, this patch may > improve the performance a little and then lead to the big change to the > test result.
No problem; thanks for confirming.
[...]
> OK, I see. What do you think if I send a v2 patch that only adds ifdeffery > to > > arch/arm64/kernel/entry.S and leave the rework to ALERNATIVE behind?
I think that would be reasonable given we do that for other bits in entry.S; I'd be happy with such a patch.
Thanks, Mark.
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