perf_counter: add PERF_RECORD_CPU

Allow recording the CPU number the event was generated on.

RFC: this leaves a u32 as reserved, should we fill in the
     node_id() there, or leave this open for future extention,
     as userspace can already easily do the cpu->node mapping
     if needed.

[ Impact: extend perfcounter output record format ]

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090508170029.008627711@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 0e6303d..614f921 100644 (file)
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -105,6 +105,7 @@ enum perf_counter_record_format {
        PERF_RECORD_GROUP       = 1U << 4,
        PERF_RECORD_CALLCHAIN   = 1U << 5,
        PERF_RECORD_CONFIG      = 1U << 6,
+       PERF_RECORD_CPU         = 1U << 7,
 };
 
 /*
@@ -260,6 +261,7 @@ enum perf_event_type {
         *      { u64                   time;     } && PERF_RECORD_TIME
         *      { u64                   addr;     } && PERF_RECORD_ADDR
         *      { u64                   config;   } && PERF_RECORD_CONFIG
+        *      { u32                   cpu, res; } && PERF_RECORD_CPU
         *
         *      { u64                   nr;
         *        { u64 event, val; }   cnt[nr];  } && PERF_RECORD_GROUP

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index c615f52..d850a1f 100644 (file)
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1956,6 +1956,9 @@ static void perf_counter_output(struct perf_counter *counter,
        struct perf_callchain_entry *callchain = NULL;
        int callchain_size = 0;
        u64 time;
+       struct {
+               u32 cpu, reserved;
+       } cpu_entry;
 
        header.type = 0;
        header.size = sizeof(header);
@@ -1999,6 +2002,13 @@ static void perf_counter_output(struct perf_counter *counter,
                header.size += sizeof(u64);
        }
 
+       if (record_type & PERF_RECORD_CPU) {
+               header.type |= PERF_RECORD_CPU;
+               header.size += sizeof(cpu_entry);
+
+               cpu_entry.cpu = raw_smp_processor_id();
+       }
+
        if (record_type & PERF_RECORD_GROUP) {
                header.type |= PERF_RECORD_GROUP;
                header.size += sizeof(u64) +
@@ -2037,6 +2047,9 @@ static void perf_counter_output(struct perf_counter *counter,
        if (record_type & PERF_RECORD_CONFIG)
                perf_output_put(&handle, counter->hw_event.config);
 
+       if (record_type & PERF_RECORD_CPU)
+               perf_output_put(&handle, cpu_entry);
+
        /*
         * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
         */