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authorLin Ming <ming.m.lin@intel.com>2010-04-23 09:56:00 +0400
committerIngo Molnar <mingo@elte.hu>2010-05-07 13:31:02 +0400
commit6bde9b6ce0127e2a56228a2071536d422be31336 (patch)
tree1a1f2fe3dbb741d81b0c08f1822ef7c0af01f91d /kernel/perf_event.c
parentab608344bcbde4f55ec4cd911b686b0ce3eae076 (diff)
downloadlinux-6bde9b6ce0127e2a56228a2071536d422be31336.tar.xz
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 'kernel/perf_event.c')
-rw-r--r--kernel/perf_event.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 34659d4085c7..bb06382f98e7 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -83,14 +83,6 @@ extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
void __weak hw_perf_disable(void) { barrier(); }
void __weak hw_perf_enable(void) { barrier(); }
-int __weak
-hw_perf_group_sched_in(struct perf_event *group_leader,
- struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx)
-{
- return 0;
-}
-
void __weak perf_event_print_debug(void) { }
static DEFINE_PER_CPU(int, perf_disable_count);
@@ -644,15 +636,20 @@ group_sched_in(struct perf_event *group_event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
- struct perf_event *event, *partial_group;
+ struct perf_event *event, *partial_group = NULL;
+ const struct pmu *pmu = group_event->pmu;
+ bool txn = false;
int ret;
if (group_event->state == PERF_EVENT_STATE_OFF)
return 0;
- ret = hw_perf_group_sched_in(group_event, cpuctx, ctx);
- if (ret)
- return ret < 0 ? ret : 0;
+ /* Check if group transaction availabe */
+ if (pmu->start_txn)
+ txn = true;
+
+ if (txn)
+ pmu->start_txn(pmu);
if (event_sched_in(group_event, cpuctx, ctx))
return -EAGAIN;
@@ -667,9 +664,19 @@ group_sched_in(struct perf_event *group_event,
}
}
- return 0;
+ if (txn) {
+ ret = pmu->commit_txn(pmu);
+ if (!ret) {
+ pmu->cancel_txn(pmu);
+
+ return 0;
+ }
+ }
group_error:
+ if (txn)
+ pmu->cancel_txn(pmu);
+
/*
* Groups can be scheduled in as one unit only, so undo any
* partial group before returning: