diff options
| author | James Hogan <james.hogan@imgtec.com> | 2013-02-27 16:16:38 +0000 |
|---|---|---|
| committer | James Hogan <james.hogan@imgtec.com> | 2013-03-15 13:20:00 +0000 |
| commit | db59932f62386cdfd8510c27a83118c5e915e9ea (patch) | |
| tree | f644aaf9845d16b7da415beb3b1a41b8744eed1c /arch/metag | |
| parent | c43ca04b5e7854b3996f84a495e4553941e76266 (diff) | |
metag: perf: fixes for interrupting perf counters
The overflow handler needs to read modify write when re-enabling the
counter so as not to change the counter value as it may have been
changed to ready the next interrupt on overflow. Similarly for
interrupting counters metag_pmu_enable_counter needs to leave the
counter value unchanged rather than resetting it to zero.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Diffstat (limited to 'arch/metag')
| -rw-r--r-- | arch/metag/kernel/perf/perf_event.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/arch/metag/kernel/perf/perf_event.c b/arch/metag/kernel/perf/perf_event.c index 8096db2a550..a00f527eade 100644 --- a/arch/metag/kernel/perf/perf_event.c +++ b/arch/metag/kernel/perf/perf_event.c @@ -643,13 +643,15 @@ static void metag_pmu_enable_counter(struct hw_perf_event *event, int idx) config = tmp >> 4; } - /* - * Enabled counters start from 0. Early cores clear the count on - * write but newer cores don't, so we make sure that the count is - * set to 0. - */ tmp = ((config & 0xf) << 28) | ((1 << 24) << cpu_2_hwthread_id[get_cpu()]); + if (metag_pmu->max_period) + /* + * Cores supporting overflow interrupts may have had the counter + * set to a specific value that needs preserving. + */ + tmp |= metag_in32(PERF_COUNT(idx)) & 0x00ffffff; + metag_out32(tmp, PERF_COUNT(idx)); unlock: raw_spin_unlock_irqrestore(&events->pmu_lock, flags); @@ -764,10 +766,16 @@ static irqreturn_t metag_pmu_counter_overflow(int irq, void *dev) /* * Enable the counter again once core overflow processing has - * completed. + * completed. Note the counter value may have been modified while it was + * inactive to set it up ready for the next interrupt. */ - if (!perf_event_overflow(event, &sampledata, regs)) + if (!perf_event_overflow(event, &sampledata, regs)) { + __global_lock2(flags); + counter = (counter & 0xff000000) | + (metag_in32(PERF_COUNT(idx)) & 0x00ffffff); metag_out32(counter, PERF_COUNT(idx)); + __global_unlock2(flags); + } return IRQ_HANDLED; } |