Re: [PATCH v3 3/6] ARCv2: perf: Support sampling events using overflow interrupts
From: Peter Zijlstra <peterz@infradead.org>
Date: 2015-08-26 13:12:37
Also in:
lkml
On Mon, Aug 24, 2015 at 05:20:20PM +0300, Alexey Brodkin wrote:
quoted hunk ↗ jump to hunk
@@ -295,6 +317,16 @@ static int arc_pmu_add(struct perf_event *event, int flags) } write_aux_reg(ARC_REG_PCT_INDEX, idx); + + arc_pmu->act_counter[idx] = event; + + if (is_sampling_event(event)) { + /* Mimic full counter overflow as other arches do */ + write_aux_reg(ARC_REG_PCT_INT_CNTL, (u32)arc_pmu->max_period); + write_aux_reg(ARC_REG_PCT_INT_CNTH, + (arc_pmu->max_period >> 32)); + } +
pmu::add should call pmu::start when PERF_EF_START, without that it should not start the counter, only schedule it. (although currently all pmu::add() calls will have EF_START set)
write_aux_reg(ARC_REG_PCT_CONFIG, 0); write_aux_reg(ARC_REG_PCT_COUNTL, 0); write_aux_reg(ARC_REG_PCT_COUNTH, 0);