tree ada38f4e1aa644354b9de4c2cb128719e9e64a9e
parent 5cbc19a983141729d716be17197028434127b376
author Peter Zijlstra <a.p.zijlstra@chello.nl> 1251892158 +0200
committer Ingo Molnar <mingo@elte.hu> 1253026287 +0200

x86: sched: Provide arch implementations using aperf/mperf

APERF/MPERF support for cpu_power.

APERF/MPERF is arch defined to be a relative scale of work capacity
per logical cpu, this is assumed to include SMT and Turbo mode.

APERF/MPERF are specified to both reset to 0 when either counter
wraps, which is highly inconvenient, since that'll give a blimp
when that happens. The manual specifies writing 0 to the counters
after each read, but that's 1) too expensive, and 2) destroys the
possibility of sharing these counters with other users, so we live
with the blimp - the other existing user does too.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>