Hi Jisheng, On Fri, Feb 20, 2026 at 05:09:22PM +0800, Jisheng Zhang wrote: > Currently, on arm64 platforms, the handle_arch_irq is a pointer which > is set during booting, and every irq processing needs to access it, > so it sits in hot code path. We can use the runtime constant mechanism > which was introduced by Linus to speed up its accessing. > > Tested on Quad CA55 platform, the perf sched benchmark is improved > by ~6.5%
6.5% is a quite high margin, especially for only one pointer's change. Maybe it is good to share more info for which compiler you are using, how you tested and the detailed results. I played a bit on my juno board on CA73 cores with the command: perf bench sched all Run 3 iterations, and measures three metrics (messaging/pipe/seccomp) and results in seconds. Less is better. +---------------------+--------+--------+--------+--------+ |Without change | run1 | run2 | run3 | avg | +---------------------+--------+--------+--------+--------+ |messaging (sec) | 4.546 | 4.508 | 4.591 | 4.548 | |pipe (sec) | 24.258 | 24.224 | 24.017 | 24.166 | |seccomp-notify (sec) | 48.393 | 48.457 | 48.232 | 48.361 | +---------------------+--------+--------+--------+--------+ +---------------------+--------+--------+--------+--------+--------+ |With change | run1 | run2 | run3 | avg | diff | +---------------------+--------+--------+--------+--------+--------+ |messaging (sec) | 4.493 | 4.523 | 4.556 | 4.524 | +0.52% | |pipe (sec) | 23.159 | 23.702 | 28.649 | 25.170 | -4.15% | |seccomp-notify (sec) | 46.848 | 46.938 | 46.973 | 46.920 | +2.98% | +---------------------+--------+--------+--------+--------+--------+ With this patch, the messaging test shows a minor improvement (0.52%). The pipe test performs worse (-4.15%) after applying the patch. However, one positive signal is that the minimum latency is 23.159, which is lower than without the change (24.017). For seccomp, the results indicate a benefit (2.98%) from the change. Hope this is helpful for maintainers to judge the change. I'd leave maintainers to review the code. Thanks, Leo
