On 09/02/2022 14:54, Peter Zijlstra wrote:
> On Wed, Feb 09, 2022 at 10:49:19AM +0200, Adrian Hunter wrote:
>> native_perf_sched_clock_from_tsc() is used to produce a time value that can
>> be consistent with perf_clock(). Consequently, it should be adjusted by
>> __sched_clock_offset, the same as perf_clock() would be.
>>
>> Fixes: 698eff6355f735 ("sched/clock, x86/perf: Fix perf test tsc")
>> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>> ---
>> arch/x86/kernel/tsc.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
>> index a698196377be..c1c73fe324cd 100644
>> --- a/arch/x86/kernel/tsc.c
>> +++ b/arch/x86/kernel/tsc.c
>> @@ -242,7 +242,8 @@ u64 native_sched_clock(void)
>> */
>> u64 native_sched_clock_from_tsc(u64 tsc)
>> {
>> - return cycles_2_ns(tsc);
>> + return cycles_2_ns(tsc) +
>> + (sched_clock_stable() ? __sched_clock_offset : 0);
>> }
>
> Why do we care about the !sched_clock_stable() case?
I guess we don't. So add __sched_clock_offset unconditionally then?
