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authorLin Ming <ming.m.lin@intel.com>2010-04-23 13:56:00 +0800
committerIngo Molnar <mingo@elte.hu>2010-05-07 11:31:02 +0200
commit6bde9b6ce0127e2a56228a2071536d422be31336 (patch)
tree1a1f2fe3dbb741d81b0c08f1822ef7c0af01f91d /include
parentab608344bcbde4f55ec4cd911b686b0ce3eae076 (diff)
perf: Add group scheduling transactional APIs
Add group scheduling transactional APIs to struct pmu. These APIs will be implemented in arch code, based on Peter's idea as below. > the idea behind hw_perf_group_sched_in() is to not perform > schedulability tests on each event in the group, but to add the group > as a whole and then perform one test. > > Of course, when that test fails, you'll have to roll-back the whole > group again. > > So start_txn (or a better name) would simply toggle a flag in the pmu > implementation that will make pmu::enable() not perform the > schedulablilty test. > > Then commit_txn() will perform the schedulability test (so note the > method has to have a !void return value. > > This will allow us to use the regular > kernel/perf_event.c::group_sched_in() and all the rollback code. > Currently each hw_perf_group_sched_in() implementation duplicates all > the rolllback code (with various bugs). ->start_txn: Start group events scheduling transaction, set a flag to make pmu::enable() not perform the schedulability test, it will be performed at commit time. ->commit_txn: Commit group events scheduling transaction, perform the group schedulability as a whole ->cancel_txn: Stop group events scheduling transaction, clear the flag so pmu::enable() will perform the schedulability test. Reviewed-by: Stephane Eranian <eranian@google.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Lin Ming <ming.m.lin@intel.com> Cc: David Miller <davem@davemloft.net> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1272002160.5707.60.camel@minggr.sh.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include')
-rw-r--r--include/linux/perf_event.h15
1 files changed, 12 insertions, 3 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 23cd0057a68..4924c96d7e2 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -547,6 +547,8 @@ struct hw_perf_event {
struct perf_event;
+#define PERF_EVENT_TXN_STARTED 1
+
/**
* struct pmu - generic performance monitoring unit
*/
@@ -557,6 +559,16 @@ struct pmu {
void (*stop) (struct perf_event *event);
void (*read) (struct perf_event *event);
void (*unthrottle) (struct perf_event *event);
+
+ /*
+ * group events scheduling is treated as a transaction,
+ * add group events as a whole and perform one schedulability test.
+ * If test fails, roll back the whole group
+ */
+
+ void (*start_txn) (const struct pmu *pmu);
+ void (*cancel_txn) (const struct pmu *pmu);
+ int (*commit_txn) (const struct pmu *pmu);
};
/**
@@ -823,9 +835,6 @@ extern void perf_disable(void);
extern void perf_enable(void);
extern int perf_event_task_disable(void);
extern int perf_event_task_enable(void);
-extern int hw_perf_group_sched_in(struct perf_event *group_leader,
- struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx);
extern void perf_event_update_userpage(struct perf_event *event);
extern int perf_event_release_kernel(struct perf_event *event);
extern struct perf_event *