Messages in this thread | | | Date | Wed, 15 Jul 2020 10:38:00 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 2/6] arm64: perf: Implement correct cap_user_time |
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On Wed, Jul 15, 2020 at 10:05:08AM +0800, Leo Yan wrote:
> [leoyan: Use quot/rem to convert cyc to ns to avoid overflow]
> + quot = rd->epoch_cyc >> rd->shift; > + rem = rd->epoch_cyc & (((u64)1 << rd->shift) - 1); > + ns = quot * rd->mult + ((rem * rd->mult) >> rd->shift); > + userpg->time_zero -= ns;
I think we have mul_u64_u32_shr() for that.
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