perf: Rework/fix the whole read vs group stuff
Replace PERF_SAMPLE_GROUP with PERF_SAMPLE_READ and introduce
PERF_FORMAT_GROUP to deal with group reads in a more generic
way.
This allows you to get group reads out of read() as well.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey J Ashford <cjashfor@us.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
LKML-Reference: <20090813103655.117411814@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 2b36afe..b53f700 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -115,7 +115,7 @@
PERF_SAMPLE_TID = 1U << 1,
PERF_SAMPLE_TIME = 1U << 2,
PERF_SAMPLE_ADDR = 1U << 3,
- PERF_SAMPLE_GROUP = 1U << 4,
+ PERF_SAMPLE_READ = 1U << 4,
PERF_SAMPLE_CALLCHAIN = 1U << 5,
PERF_SAMPLE_ID = 1U << 6,
PERF_SAMPLE_CPU = 1U << 7,
@@ -127,16 +127,32 @@
};
/*
- * Bits that can be set in attr.read_format to request that
- * reads on the counter should return the indicated quantities,
- * in increasing order of bit value, after the counter value.
+ * The format of the data returned by read() on a perf counter fd,
+ * as specified by attr.read_format:
+ *
+ * struct read_format {
+ * { u64 value;
+ * { u64 time_enabled; } && PERF_FORMAT_ENABLED
+ * { u64 time_running; } && PERF_FORMAT_RUNNING
+ * { u64 id; } && PERF_FORMAT_ID
+ * } && !PERF_FORMAT_GROUP
+ *
+ * { u64 nr;
+ * { u64 time_enabled; } && PERF_FORMAT_ENABLED
+ * { u64 time_running; } && PERF_FORMAT_RUNNING
+ * { u64 value;
+ * { u64 id; } && PERF_FORMAT_ID
+ * } cntr[nr];
+ * } && PERF_FORMAT_GROUP
+ * };
*/
enum perf_counter_read_format {
PERF_FORMAT_TOTAL_TIME_ENABLED = 1U << 0,
PERF_FORMAT_TOTAL_TIME_RUNNING = 1U << 1,
PERF_FORMAT_ID = 1U << 2,
+ PERF_FORMAT_GROUP = 1U << 3,
- PERF_FORMAT_MAX = 1U << 3, /* non-ABI */
+ PERF_FORMAT_MAX = 1U << 4, /* non-ABI */
};
#define PERF_ATTR_SIZE_VER0 64 /* sizeof first published struct */
@@ -343,10 +359,8 @@
* struct {
* struct perf_event_header header;
* u32 pid, tid;
- * u64 value;
- * { u64 time_enabled; } && PERF_FORMAT_ENABLED
- * { u64 time_running; } && PERF_FORMAT_RUNNING
- * { u64 parent_id; } && PERF_FORMAT_ID
+ *
+ * struct read_format values;
* };
*/
PERF_EVENT_READ = 8,
@@ -364,11 +378,22 @@
* { u32 cpu, res; } && PERF_SAMPLE_CPU
* { u64 period; } && PERF_SAMPLE_PERIOD
*
- * { u64 nr;
- * { u64 id, val; } cnt[nr]; } && PERF_SAMPLE_GROUP
+ * { struct read_format values; } && PERF_SAMPLE_READ
*
* { u64 nr,
* u64 ips[nr]; } && PERF_SAMPLE_CALLCHAIN
+ *
+ * #
+ * # The RAW record below is opaque data wrt the ABI
+ * #
+ * # That is, the ABI doesn't make any promises wrt to
+ * # the stability of its content, it may vary depending
+ * # on event, hardware, kernel version and phase of
+ * # the moon.
+ * #
+ * # In other words, PERF_SAMPLE_RAW contents are not an ABI.
+ * #
+ *
* { u32 size;
* char data[size];}&& PERF_SAMPLE_RAW
* };