From 2023b359214bbc5bad31571cf50d7fb83b535c0a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 May 2009 17:50:26 +0200 Subject: [PATCH] perf_counter: inheritable sample counters Redirect the output to the parent counter and put in some sanity checks. [ Impact: new perfcounter feature - inherited sampling counters ] Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Corey Ashford LKML-Reference: <20090505155437.331556171@chello.nl> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index c881afef997..60e55f0b48f 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -738,10 +738,18 @@ static void perf_counter_enable(struct perf_counter *counter) spin_unlock_irq(&ctx->lock); } -static void perf_counter_refresh(struct perf_counter *counter, int refresh) +static int perf_counter_refresh(struct perf_counter *counter, int refresh) { + /* + * not supported on inherited counters + */ + if (counter->hw_event.inherit) + return -EINVAL; + atomic_add(refresh, &counter->event_limit); perf_counter_enable(counter); + + return 0; } /* @@ -1307,7 +1315,7 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) perf_counter_disable_family(counter); break; case PERF_COUNTER_IOC_REFRESH: - perf_counter_refresh(counter, arg); + err = perf_counter_refresh(counter, arg); break; case PERF_COUNTER_IOC_RESET: perf_counter_reset(counter); @@ -1814,6 +1822,12 @@ static int perf_output_begin(struct perf_output_handle *handle, struct perf_mmap_data *data; unsigned int offset, head; + /* + * For inherited counters we send all the output towards the parent. + */ + if (counter->parent) + counter = counter->parent; + rcu_read_lock(); data = rcu_dereference(counter->data); if (!data) @@ -1995,6 +2009,9 @@ static void perf_counter_output(struct perf_counter *counter, if (record_type & PERF_RECORD_ADDR) perf_output_put(&handle, addr); + /* + * XXX PERF_RECORD_GROUP vs inherited counters seems difficult. + */ if (record_type & PERF_RECORD_GROUP) { struct perf_counter *leader, *sub; u64 nr = counter->nr_siblings; @@ -2281,6 +2298,11 @@ int perf_counter_overflow(struct perf_counter *counter, int events = atomic_read(&counter->event_limit); int ret = 0; + /* + * XXX event_limit might not quite work as expected on inherited + * counters + */ + counter->pending_kill = POLL_IN; if (events && atomic_dec_and_test(&counter->event_limit)) { ret = 1; @@ -2801,6 +2823,12 @@ perf_counter_alloc(struct perf_counter_hw_event *hw_event, pmu = NULL; + /* + * we currently do not support PERF_RECORD_GROUP on inherited counters + */ + if (hw_event->inherit && (hw_event->record_type & PERF_RECORD_GROUP)) + goto done; + if (perf_event_raw(hw_event)) { pmu = hw_perf_counter_init(counter); goto done;