From: Kan Liang <kan.li...@intel.com> There are two free-running counters for client IMC uncore. The customized event_init() function hard codes their index to 'UNCORE_PMC_IDX_FIXED' and 'UNCORE_PMC_IDX_FIXED + 1'. To support the index 'UNCORE_PMC_IDX_FIXED + 1', the generic uncore_perf_event_update is obscurely hacked. The code quality issue will bring problems when a new counter index is introduced into the generic code, for example, a new index for free-running counter.
Introducing a customized event_read() function for client IMC uncore. The customized function is copied from previous generic uncore_pmu_event_read(). The index 'UNCORE_PMC_IDX_FIXED + 1' will be isolated for client IMC uncore only. Reviewed-by: Thomas Gleixner <t...@linutronix.de> Signed-off-by: Kan Liang <kan.li...@intel.com> --- Changes since V6 - Refine changelog arch/x86/events/intel/uncore_snb.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/arch/x86/events/intel/uncore_snb.c b/arch/x86/events/intel/uncore_snb.c index aee5e84..df53521 100644 --- a/arch/x86/events/intel/uncore_snb.c +++ b/arch/x86/events/intel/uncore_snb.c @@ -450,6 +450,35 @@ static void snb_uncore_imc_event_start(struct perf_event *event, int flags) uncore_pmu_start_hrtimer(box); } +static void snb_uncore_imc_event_read(struct perf_event *event) +{ + struct intel_uncore_box *box = uncore_event_to_box(event); + u64 prev_count, new_count, delta; + int shift; + + /* + * There are two free running counters in IMC. + * The index for the second one is hardcoded to + * UNCORE_PMC_IDX_FIXED + 1. + */ + if (event->hw.idx >= UNCORE_PMC_IDX_FIXED) + shift = 64 - uncore_fixed_ctr_bits(box); + else + shift = 64 - uncore_perf_ctr_bits(box); + + /* the hrtimer might modify the previous event value */ +again: + prev_count = local64_read(&event->hw.prev_count); + new_count = uncore_read_counter(box, event); + if (local64_xchg(&event->hw.prev_count, new_count) != prev_count) + goto again; + + delta = (new_count << shift) - (prev_count << shift); + delta >>= shift; + + local64_add(delta, &event->count); +} + static void snb_uncore_imc_event_stop(struct perf_event *event, int flags) { struct intel_uncore_box *box = uncore_event_to_box(event); @@ -472,7 +501,7 @@ static void snb_uncore_imc_event_stop(struct perf_event *event, int flags) * Drain the remaining delta count out of a event * that we are disabling: */ - uncore_perf_event_update(box, event); + snb_uncore_imc_event_read(event); hwc->state |= PERF_HES_UPTODATE; } } @@ -534,7 +563,7 @@ static struct pmu snb_uncore_imc_pmu = { .del = snb_uncore_imc_event_del, .start = snb_uncore_imc_event_start, .stop = snb_uncore_imc_event_stop, - .read = uncore_pmu_event_read, + .read = snb_uncore_imc_event_read, }; static struct intel_uncore_ops snb_uncore_imc_ops = { -- 2.7.4