• Peter Zijlstra's avatar
    x86: sched: provide arch implementations using aperf/mperf · d65d153b
    Peter Zijlstra authored
    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: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
    Signed-off-by: default avatarDinakar Guniguntala <dino@in.ibm.com>
    Cc: John Stultz <johnstul@us.ibm.com>
    Cc: Darren Hart <dvhltc@us.ibm.com>
    Cc: John Kacur <jkacur@redhat.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    d65d153b
Makefile 1.28 KB