Re: [PATCH v2 4/8] ARCv2: perf: Support sampling events using overflow interrupts
From: Peter Zijlstra <peterz@infradead.org>
Date: 2015-08-18 22:12:24
Also in:
lkml
On Wed, Aug 05, 2015 at 06:13:30PM +0300, Alexey Brodkin wrote:
quoted hunk ↗ jump to hunk
@@ -319,6 +336,20 @@ 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)); + + /* Enable interrupt for this counter */ + write_aux_reg(ARC_REG_PCT_INT_CTRL, + read_aux_reg(ARC_REG_PCT_INT_CTRL) | (1 << idx)); + }
*confused* pmu::add should only start on flags & PERF_EF_START, and then we start with hwc->sample_period, not the max_period.
+ write_aux_reg(ARC_REG_PCT_CONFIG, 0); write_aux_reg(ARC_REG_PCT_COUNTL, 0); write_aux_reg(ARC_REG_PCT_COUNTH, 0);