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Peter Zijlstra authored
There was a bug in the old period code that caused intel_pmu_enable_all() or native_write_msr_safe() to show up quite high in the profiles. In staring at that code it made my head hurt, so I rewrote it in a hopefully simpler fashion. Its now fully symetric between tick and overflow driven adjustments and uses less data to boot. The only complication is that it basically wants to do a u128 division. The code approximates that in a rather simple truncate until it fits fashion, taking care to balance the terms while truncating. This version does not generate that sampling artefact. Signed-off-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Cc: <stable@kernel.org> Signed-off-by:
Ingo Molnar <mingo@elte.hu>
abd50713