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When the hrtimer_interrupt needs to restart more than 3 times and still has expired timers, the interrupt is considered hung. To give the system a little time to recover, the hardware timer is programmed a little into the future. Prior to commit2889243848("hrtimer: Re-arrange hrtimer_interrupt()"), this was relative to the amount of time spend serving the interrupt with a max of 100 msec. However, in order to simplify, and because this condition 'should' not happen, the timeout was unconditionally set to 100 msec. 'Obviously' there is a benchmark that hits this hard, by programming a ton of very short timers :-/ Since reprogramming is decoupled from the interrupt handling, the actual execution time is lost, however the code does track max_hang_time. Using that, rather than the 100 ms max restores performance. stress-ng --timeout 60 --times --verify --metrics --no-rand-seed --timermix 64 bogo ops/s 288924384856^1: 23715979.932889243848: 11550049.77 patched: 23361116.78 Additionally, Thomas noted that cpu_base->hang_detected should not be cleared until the next interrupt, such that __hrtimer_reprogram() won't undo the extra delay. Fixes:2889243848("hrtimer: Re-arrange hrtimer_interrupt()") Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260311121500.GF652779@noisy.programming.kicks-ass.net Closes: https://lore.kernel.org/oe-lkp/202603102229.74b9dee4-lkp@intel.com