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Subject[PATCH 4/4] perf, tools: Add perf stat --transaction v5
Date
From: Andi Kleen <ak@linux.intel.com>

Add support to perf stat to print the basic transactional execution statistics:
Total cycles, Cycles in Transaction, Cycles in aborted transsactions
using the in_tx and in_tx_checkpoint qualifiers.
Transaction Starts and Elision Starts, to compute the average transaction
length.

This is a reasonable overview over the success of the transactions.

Also support architectures that have a transaction aborted cycles
counter like POWER8. Since that is awkward to handle in the kernel
abstract handle both cases here.

Enable with a new --transaction / -T option.

This requires measuring these events in a group, since they depend on each
other.

This is implemented by using TM sysfs events exported by the kernel

v2: Only print the extended statistics when the option is enabled.
This avoids negative output when the user specifies the -T events
in separate groups.
v3: Port to latest tree
v4: Remove merge error. Avoid linear walks for comparisons. Check
transaction_run earlier. Minor fixes.
v5: Move option to avoid conflict. Improve description.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
tools/perf/Documentation/perf-stat.txt | 5 ++
tools/perf/builtin-stat.c | 144 ++++++++++++++++++++++++++++++++-
tools/perf/util/evsel.h | 6 ++
tools/perf/util/pmu.c | 16 ++++
tools/perf/util/pmu.h | 1 +
5 files changed, 171 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 2fe87fb..40bc65a 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -132,6 +132,11 @@ is a useful mode to detect imbalance between physical cores. To enable this mod
use --per-core in addition to -a. (system-wide). The output includes the
core number and the number of online logical processors on that physical processor.

+-T::
+--transaction::
+
+Print statistics of transactional execution if supported.
+
EXAMPLES
--------

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 352fbd7..6bd90e4 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -46,6 +46,7 @@
#include "util/util.h"
#include "util/parse-options.h"
#include "util/parse-events.h"
+#include "util/pmu.h"
#include "util/event.h"
#include "util/evlist.h"
#include "util/evsel.h"
@@ -70,6 +71,41 @@ static void print_counter_aggr(struct perf_evsel *counter, char *prefix);
static void print_counter(struct perf_evsel *counter, char *prefix);
static void print_aggr(char *prefix);

+/* Default events used for perf stat -T */
+static const char * const transaction_attrs[] = {
+ "task-clock",
+ "{"
+ "instructions,"
+ "cycles,"
+ "cpu/cycles-t/,"
+ "cpu/tx-start/,"
+ "cpu/el-start/,"
+ "cpu/cycles-ct/"
+ "}"
+};
+
+/* More limited version when the CPU does not have all events. */
+static const char * const transaction_limited_attrs[] = {
+ "task-clock",
+ "{"
+ "instructions,"
+ "cycles,"
+ "cpu/cycles-t/,"
+ "cpu/tx-start/"
+ "}"
+};
+
+/* must match transaction_attrs and the beginning limited_attrs */
+enum {
+ T_TASK_CLOCK,
+ T_INSTRUCTIONS,
+ T_CYCLES,
+ T_CYCLES_IN_TX,
+ T_TRANSACTION_START,
+ T_ELISION_START,
+ T_CYCLES_IN_TX_CP,
+};
+
static struct perf_evlist *evsel_list;

static struct perf_target target = {
@@ -90,6 +126,7 @@ static enum aggr_mode aggr_mode = AGGR_GLOBAL;
static volatile pid_t child_pid = -1;
static bool null_run = false;
static int detailed_run = 0;
+static bool transaction_run;
static bool big_num = true;
static int big_num_opt = -1;
static const char *csv_sep = NULL;
@@ -213,7 +250,10 @@ static struct stats runtime_l1_icache_stats[MAX_NR_CPUS];
static struct stats runtime_ll_cache_stats[MAX_NR_CPUS];
static struct stats runtime_itlb_cache_stats[MAX_NR_CPUS];
static struct stats runtime_dtlb_cache_stats[MAX_NR_CPUS];
+static struct stats runtime_cycles_in_tx_stats[MAX_NR_CPUS];
static struct stats walltime_nsecs_stats;
+static struct stats runtime_transaction_stats[MAX_NR_CPUS];
+static struct stats runtime_elision_stats[MAX_NR_CPUS];

static void perf_stat__reset_stats(struct perf_evlist *evlist)
{
@@ -235,6 +275,11 @@ static void perf_stat__reset_stats(struct perf_evlist *evlist)
memset(runtime_ll_cache_stats, 0, sizeof(runtime_ll_cache_stats));
memset(runtime_itlb_cache_stats, 0, sizeof(runtime_itlb_cache_stats));
memset(runtime_dtlb_cache_stats, 0, sizeof(runtime_dtlb_cache_stats));
+ memset(runtime_cycles_in_tx_stats, 0,
+ sizeof(runtime_cycles_in_tx_stats));
+ memset(runtime_transaction_stats, 0,
+ sizeof(runtime_transaction_stats));
+ memset(runtime_elision_stats, 0, sizeof(runtime_elision_stats));
memset(&walltime_nsecs_stats, 0, sizeof(walltime_nsecs_stats));
}

@@ -272,6 +317,29 @@ static inline int nsec_counter(struct perf_evsel *evsel)
return 0;
}

+static struct perf_evsel *nth_evsel(int n)
+{
+ static struct perf_evsel **array;
+ static int array_len;
+ struct perf_evsel *ev;
+ int j;
+
+ /* Assumes this only called when evsel_list does not change anymore. */
+ if (!array) {
+ list_for_each_entry(ev, &evsel_list->entries, node)
+ array_len++;
+ array = malloc(array_len * sizeof(void *));
+ if (!array)
+ exit(ENOMEM);
+ j = 0;
+ list_for_each_entry(ev, &evsel_list->entries, node)
+ array[j++] = ev;
+ }
+ if (n < array_len)
+ return array[n];
+ return NULL;
+}
+
/*
* Update various tracking values we maintain to print
* more semantic information such as miss/hit ratios,
@@ -283,6 +351,15 @@ static void update_shadow_stats(struct perf_evsel *counter, u64 *count)
update_stats(&runtime_nsecs_stats[0], count[0]);
else if (perf_evsel__match(counter, HARDWARE, HW_CPU_CYCLES))
update_stats(&runtime_cycles_stats[0], count[0]);
+ else if (transaction_run &&
+ perf_evsel__cmp(counter, nth_evsel(T_CYCLES_IN_TX)))
+ update_stats(&runtime_cycles_in_tx_stats[0], count[0]);
+ else if (transaction_run &&
+ perf_evsel__cmp(counter, nth_evsel(T_TRANSACTION_START)))
+ update_stats(&runtime_transaction_stats[0], count[0]);
+ else if (transaction_run &&
+ perf_evsel__cmp(counter, nth_evsel(T_ELISION_START)))
+ update_stats(&runtime_elision_stats[0], count[0]);
else if (perf_evsel__match(counter, HARDWARE, HW_STALLED_CYCLES_FRONTEND))
update_stats(&runtime_stalled_cycles_front_stats[0], count[0]);
else if (perf_evsel__match(counter, HARDWARE, HW_STALLED_CYCLES_BACKEND))
@@ -807,7 +884,7 @@ static void print_ll_cache_misses(int cpu,

static void abs_printout(int cpu, int nr, struct perf_evsel *evsel, double avg)
{
- double total, ratio = 0.0;
+ double total, ratio = 0.0, total2;
const char *fmt;

if (csv_output)
@@ -903,6 +980,43 @@ static void abs_printout(int cpu, int nr, struct perf_evsel *evsel, double avg)
ratio = 1.0 * avg / total;

fprintf(output, " # %8.3f GHz ", ratio);
+ } else if (transaction_run &&
+ perf_evsel__cmp(evsel, nth_evsel(T_CYCLES_IN_TX))) {
+ total = avg_stats(&runtime_cycles_stats[cpu]);
+ if (total)
+ fprintf(output,
+ " # %5.2f%% transactional cycles ",
+ 100.0 * (avg / total));
+ } else if (transaction_run &&
+ perf_evsel__cmp(evsel, nth_evsel(T_CYCLES_IN_TX_CP))) {
+ total = avg_stats(&runtime_cycles_stats[cpu]);
+ total2 = avg_stats(&runtime_cycles_in_tx_stats[cpu]);
+ if (total2 < avg)
+ total2 = avg;
+ if (total)
+ fprintf(output,
+ " # %5.2f%% aborted cycles ",
+ 100.0 * ((total2-avg) / total));
+ } else if (transaction_run &&
+ perf_evsel__cmp(evsel, nth_evsel(T_TRANSACTION_START)) &&
+ avg > 0 &&
+ runtime_cycles_in_tx_stats[cpu].n != 0) {
+ total = avg_stats(&runtime_cycles_in_tx_stats[cpu]);
+
+ if (total)
+ ratio = total / avg;
+
+ fprintf(output, " # %8.0f cycles / transaction ", ratio);
+ } else if (transaction_run &&
+ perf_evsel__cmp(evsel, nth_evsel(T_ELISION_START)) &&
+ avg > 0 &&
+ runtime_cycles_in_tx_stats[cpu].n != 0) {
+ total = avg_stats(&runtime_cycles_in_tx_stats[cpu]);
+
+ if (total)
+ ratio = total / avg;
+
+ fprintf(output, " # %8.0f cycles / elision ", ratio);
} else if (runtime_nsecs_stats[cpu].n != 0) {
char unit = 'M';

@@ -1216,6 +1330,16 @@ static int perf_stat_init_aggr_mode(void)
return 0;
}

+static int setup_events(const char * const *attrs, unsigned len)
+{
+ unsigned i;
+
+ for (i = 0; i < len; i++) {
+ if (parse_events(evsel_list, attrs[i]))
+ return -1;
+ }
+ return 0;
+}

/*
* Add default attributes, if there were no attributes specified or
@@ -1334,6 +1458,22 @@ static int add_default_attributes(void)
if (null_run)
return 0;

+ if (transaction_run) {
+ int err;
+ if (pmu_have_event("cpu", "cycles-ct") &&
+ pmu_have_event("cpu", "el-start"))
+ err = setup_events(transaction_attrs,
+ ARRAY_SIZE(transaction_attrs));
+ else
+ err = setup_events(transaction_limited_attrs,
+ ARRAY_SIZE(transaction_limited_attrs));
+ if (err < 0) {
+ fprintf(stderr, "Cannot set up transaction events\n");
+ return -1;
+ }
+ return 0;
+ }
+
if (!evsel_list->nr_entries) {
if (perf_evlist__add_default_attrs(evsel_list, default_attrs) < 0)
return -1;
@@ -1368,6 +1508,8 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
int output_fd = 0;
const char *output_name = NULL;
const struct option options[] = {
+ OPT_BOOLEAN('T', "transaction", &transaction_run,
+ "hardware transaction statistics"),
OPT_CALLBACK('e', "event", &evsel_list, "event",
"event selector. use 'perf list' to list available events",
parse_events_option),
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 3f156cc..2f3dc86 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -180,6 +180,12 @@ static inline bool perf_evsel__match2(struct perf_evsel *e1,
(e1->attr.config == e2->attr.config);
}

+#define perf_evsel__cmp(a, b) \
+ ((a) && \
+ (b) && \
+ (a)->attr.type == (b)->attr.type && \
+ (a)->attr.config == (b)->attr.config)
+
int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
int cpu, int thread, bool scale);

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index bc9d806..64362fe 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -637,3 +637,19 @@ void print_pmu_events(const char *event_glob, bool name_only)
printf("\n");
free(aliases);
}
+
+bool pmu_have_event(const char *pname, const char *name)
+{
+ struct perf_pmu *pmu;
+ struct perf_pmu_alias *alias;
+
+ pmu = NULL;
+ while ((pmu = perf_pmu__scan(pmu)) != NULL) {
+ if (strcmp(pname, pmu->name))
+ continue;
+ list_for_each_entry(alias, &pmu->aliases, list)
+ if (!strcmp(alias->name, name))
+ return true;
+ }
+ return false;
+}
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 6b2cbe2..1179b26 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -42,6 +42,7 @@ int perf_pmu__format_parse(char *dir, struct list_head *head);
struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu);

void print_pmu_events(const char *event_glob, bool name_only);
+bool pmu_have_event(const char *pname, const char *name);

int perf_pmu__test(void);
#endif /* __PMU_H */
--
1.8.3.1


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