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    SubjectRe: [PATCH -tip, final] perf, x86: Add hw_watchdog_set_attr() in a sake of nmi-watchdog on P4
    On Tue, Jul 05, 2011 at 12:20:17PM +0200, Ingo Molnar wrote:
    >
    > * Cyrill Gorcunov <gorcunov@gmail.com> wrote:
    ...
    >
    > So why don't we simply set this for all PERF_COUNT_HW_CPU_CYCLES
    > events in the P4 PMU driver? That would remove half of the patch
    > AFAICS.
    >
    > Thanks,
    >
    > Ingo

    Unfortunately it doesn't solve the main issue -- nmi-watchdog events
    and cpu clock events should be a separate events with non-intersected
    ESCRs, otherwise nmi-watchdog and cpu-cycles can't operate simultaneously
    like other PMUs does.

    non-sleeping ticks use

    [P4_EVENT_EXECUTION_EVENT] = {
    .escr_msr = { MSR_P4_CRU_ESCR2, MSR_P4_CRU_ESCR3 },
    .cntr = { {12, 13, 16}, {14, 15, 17}
    },

    while cpu-cycles

    [P4_EVENT_GLOBAL_POWER_EVENTS] = {
    .escr_msr = { MSR_P4_FSB_ESCR0, MSR_P4_FSB_ESCR1 },
    .cntr = { {0, -1, -1}, {2, -1, -1} },
    },

    Note non-intersection of { MSR_P4_CRU_ESCR2, MSR_P4_CRU_ESCR3 } and
    { MSR_P4_FSB_ESCR0, MSR_P4_FSB_ESCR1 } here (together with counters
    itselves pointed by .cntr).

    Cyrill


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