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authorSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>2015-09-04 06:07:45 +0300
committerIngo Molnar <mingo@kernel.org>2015-09-13 12:27:25 +0300
commitfbbe07011581990ef74dfac06dc8511b1a14badb (patch)
tree8b026523a68ff8d98107a393d0551c9bfbf00812 /arch/powerpc/perf
parent845583767c306dac0290aab908c18b01772ea4b4 (diff)
downloadlinux-fbbe07011581990ef74dfac06dc8511b1a14badb.tar.xz
perf/core: Add a 'flags' parameter to the PMU transactional interfaces
Currently, the PMU interface allows reading only one counter at a time. But some PMUs like the 24x7 counters in Power, support reading several counters at once. To leveage this functionality, extend the transaction interface to support a "transaction type". The first type, PERF_PMU_TXN_ADD, refers to the existing transactions, i.e. used to _schedule_ all the events on the PMU as a group. A second transaction type, PERF_PMU_TXN_READ, will be used in a follow-on patch, by the 24x7 counters to read several counters at once. Extend the transaction interfaces to the PMU to accept a 'txn_flags' parameter and use this parameter to ignore any transactions that are not of type PERF_PMU_TXN_ADD. Thanks to Peter Zijlstra for his input. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> [peterz: s390 compile fix] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1441336073-22750-3-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/powerpc/perf')
-rw-r--r--arch/powerpc/perf/core-book3s.c30
1 files changed, 29 insertions, 1 deletions
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index b0382f3f1095..c84074185c80 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -49,6 +49,7 @@ struct cpu_hw_events {
unsigned long avalues[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
unsigned int group_flag;
+ unsigned int txn_flags;
int n_txn_start;
/* BHRB bits */
@@ -1586,11 +1587,21 @@ static void power_pmu_stop(struct perf_event *event, int ef_flags)
* Start group events scheduling transaction
* Set the flag to make pmu::enable() not perform the
* schedulability test, it will be performed at commit time
+ *
+ * We only support PERF_PMU_TXN_ADD transactions. Save the
+ * transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD
+ * transactions.
*/
-static void power_pmu_start_txn(struct pmu *pmu)
+static void power_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
{
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
+ WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */
+
+ cpuhw->txn_flags = txn_flags;
+ if (txn_flags & ~PERF_PMU_TXN_ADD)
+ return;
+
perf_pmu_disable(pmu);
cpuhw->group_flag |= PERF_EVENT_TXN;
cpuhw->n_txn_start = cpuhw->n_events;
@@ -1604,6 +1615,14 @@ static void power_pmu_start_txn(struct pmu *pmu)
static void power_pmu_cancel_txn(struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
+ unsigned int txn_flags;
+
+ WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
+
+ txn_flags = cpuhw->txn_flags;
+ cpuhw->txn_flags = 0;
+ if (txn_flags & ~PERF_PMU_TXN_ADD)
+ return;
cpuhw->group_flag &= ~PERF_EVENT_TXN;
perf_pmu_enable(pmu);
@@ -1621,7 +1640,15 @@ static int power_pmu_commit_txn(struct pmu *pmu)
if (!ppmu)
return -EAGAIN;
+
cpuhw = this_cpu_ptr(&cpu_hw_events);
+ WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
+
+ if (cpuhw->txn_flags & ~PERF_PMU_TXN_ADD) {
+ cpuhw->txn_flags = 0;
+ return 0;
+ }
+
n = cpuhw->n_events;
if (check_excludes(cpuhw->event, cpuhw->flags, 0, n))
return -EAGAIN;
@@ -1633,6 +1660,7 @@ static int power_pmu_commit_txn(struct pmu *pmu)
cpuhw->event[i]->hw.config = cpuhw->events[i];
cpuhw->group_flag &= ~PERF_EVENT_TXN;
+ cpuhw->txn_flags = 0;
perf_pmu_enable(pmu);
return 0;
}