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authorSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>2015-09-03 20:07:45 -0700
committerIngo Molnar <mingo@kernel.org>2015-09-13 11:27:25 +0200
commitfbbe07011581990ef74dfac06dc8511b1a14badb (patch)
tree8b026523a68ff8d98107a393d0551c9bfbf00812 /arch/s390
parent845583767c306dac0290aab908c18b01772ea4b4 (diff)
downloadlinux-fbbe07011581990ef74dfac06dc8511b1a14badb.tar.gz
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/s390')
-rw-r--r--arch/s390/kernel/perf_cpum_cf.c30
1 files changed, 29 insertions, 1 deletions
diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index 56fdad479115..19138be412d6 100644
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -72,6 +72,7 @@ struct cpu_hw_events {
atomic_t ctr_set[CPUMF_CTR_SET_MAX];
u64 state, tx_state;
unsigned int flags;
+ unsigned int txn_flags;
};
static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
.ctr_set = {
@@ -82,6 +83,7 @@ static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
},
.state = 0,
.flags = 0,
+ .txn_flags = 0,
};
static int get_counter_set(u64 event)
@@ -572,11 +574,21 @@ static void cpumf_pmu_del(struct perf_event *event, int flags)
/*
* Start group events scheduling transaction.
* Set flags to perform a single test 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 cpumf_pmu_start_txn(struct pmu *pmu)
+static void cpumf_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->flags |= PERF_EVENT_TXN;
cpuhw->tx_state = cpuhw->state;
@@ -589,8 +601,16 @@ static void cpumf_pmu_start_txn(struct pmu *pmu)
*/
static void cpumf_pmu_cancel_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); /* no txn in flight */
+
+ txn_flags = cpuhw->txn_flags;
+ cpuhw->txn_flags = 0;
+ if (txn_flags & ~PERF_PMU_TXN_ADD)
+ return;
+
WARN_ON(cpuhw->tx_state != cpuhw->state);
cpuhw->flags &= ~PERF_EVENT_TXN;
@@ -607,6 +627,13 @@ static int cpumf_pmu_commit_txn(struct pmu *pmu)
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
u64 state;
+ WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
+
+ if (cpuhw->txn_flags & ~PERF_PMU_TXN_ADD) {
+ cpuhw->txn_flags = 0;
+ return 0;
+ }
+
/* check if the updated state can be scheduled */
state = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1);
state >>= CPUMF_LCCTL_ENABLE_SHIFT;
@@ -614,6 +641,7 @@ static int cpumf_pmu_commit_txn(struct pmu *pmu)
return -EPERM;
cpuhw->flags &= ~PERF_EVENT_TXN;
+ cpuhw->txn_flags = 0;
perf_pmu_enable(pmu);
return 0;
}