[PATCH 4/6] perf tools: Support "branch-misses:pp" on arm64

From: Tan Xiaojun
Date: Wed Dec 18 2019 - 02:09:11 EST


At the suggestion of James Clark, use spe to support the precise
ip of some events. Currently its support event is:
branch-misses.

Example usage:

$ ./perf record -e branch-misses:pp dd if=/dev/zero of=/dev/null count=10000
(:p/pp/ppp is same for this case.)

$ ./perf report --stdio
("--stdio is not necessary")

--------------------------------------------------------------------
...
# Samples: 14 of event 'branch-misses:pp'
# Event count (approx.): 14
#
# Children Self Command Shared Object Symbol
# ........ ........ ....... ................. ..........................
#
14.29% 14.29% dd [kernel.kallsyms] [k] __arch_copy_from_user
14.29% 14.29% dd libc-2.28.so [.] _dl_addr
7.14% 7.14% dd [kernel.kallsyms] [k] __free_pages
7.14% 7.14% dd [kernel.kallsyms] [k] __pi_memcpy
7.14% 7.14% dd [kernel.kallsyms] [k] pagecache_get_page
7.14% 7.14% dd [kernel.kallsyms] [k] unmap_single_vma
7.14% 7.14% dd dd [.] 0x00000000000025ec
7.14% 7.14% dd ld-2.28.so [.] _dl_lookup_symbol_x
7.14% 7.14% dd ld-2.28.so [.] check_match
7.14% 7.14% dd libc-2.28.so [.] __mpn_rshift
7.14% 7.14% dd libc-2.28.so [.] _nl_intern_locale_data
7.14% 7.14% dd libc-2.28.so [.] read_alias_file
...
--------------------------------------------------------------------

Signed-off-by: Tan Xiaojun <tanxiaojun@xxxxxxxxxx>
Suggested-by: James Clark <James.Clark@xxxxxxx>
Tested-by: Qi Liu <liuqi115@xxxxxxxxxxxxx>
---
tools/perf/util/arm-spe.c | 41 +++++++++++++++++++++++++++++++++++++++
tools/perf/util/arm-spe.h | 3 +++
tools/perf/util/evlist.c | 2 ++
3 files changed, 46 insertions(+)

diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index c99814c58745..0fcaefd386a6 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -35,6 +35,19 @@

#define MAX_TIMESTAMP (~0ULL)

+#define SPE_ATTR_TS_ENABLE BIT(0)
+#define SPE_ATTR_PA_ENABLE BIT(1)
+#define SPE_ATTR_PCT_ENABLE BIT(2)
+#define SPE_ATTR_JITTER BIT(16)
+#define SPE_ATTR_BRANCH_FILTER BIT(32)
+#define SPE_ATTR_LOAD_FILTER BIT(33)
+#define SPE_ATTR_STORE_FILTER BIT(34)
+
+#define SPE_ATTR_EV_RETIRED BIT(1)
+#define SPE_ATTR_EV_CACHE BIT(3)
+#define SPE_ATTR_EV_TLB BIT(5)
+#define SPE_ATTR_EV_BRANCH BIT(7)
+
struct arm_spe {
struct auxtrace auxtrace;
struct auxtrace_queues queues;
@@ -778,6 +791,15 @@ arm_spe_synth_events(struct arm_spe *spe, struct perf_session *session)
attr.sample_id_all = evsel->core.attr.sample_id_all;
attr.read_format = evsel->core.attr.read_format;

+ /* If it is in the precise ip mode, there is no need to
+ * synthesize new events. */
+ if (!strncmp(evsel->name, "branch-misses", 13)) {
+ spe->sample_branch_miss = true;
+ spe->branch_miss_id = evsel->core.id[0];
+
+ return 0;
+ }
+
/* create new id val to be a fixed offset from evsel id */
id = evsel->core.id[0] + 1000000000;

@@ -899,3 +921,22 @@ int arm_spe_process_auxtrace_info(union perf_event *event,
free(spe);
return err;
}
+
+void arm_spe_precise_ip_support(struct evlist *evlist, struct evsel *evsel)
+{
+ struct perf_pmu *pmu;
+
+ /* Currently only supports precise_ip for branch-misses on arm64 */
+ if (!strcmp(perf_env__arch(evlist->env), "arm64")
+ && evsel->core.attr.config == PERF_COUNT_HW_BRANCH_MISSES
+ && evsel->core.attr.precise_ip) {
+ pmu = perf_pmu__find("arm_spe_0");
+ if (pmu) {
+ evsel->pmu_name = pmu->name;
+ evsel->core.attr.type = pmu->type;
+ evsel->core.attr.config = SPE_ATTR_TS_ENABLE
+ | SPE_ATTR_BRANCH_FILTER;
+ evsel->core.attr.config1 = SPE_ATTR_EV_BRANCH;
+ }
+ }
+}
diff --git a/tools/perf/util/arm-spe.h b/tools/perf/util/arm-spe.h
index 98d3235781c3..8b1fb191d03a 100644
--- a/tools/perf/util/arm-spe.h
+++ b/tools/perf/util/arm-spe.h
@@ -20,6 +20,8 @@ enum {
union perf_event;
struct perf_session;
struct perf_pmu;
+struct evlist;
+struct evsel;

struct auxtrace_record *arm_spe_recording_init(int *err,
struct perf_pmu *arm_spe_pmu);
@@ -28,4 +30,5 @@ int arm_spe_process_auxtrace_info(union perf_event *event,
struct perf_session *session);

struct perf_event_attr *arm_spe_pmu_default_config(struct perf_pmu *arm_spe_pmu);
+void arm_spe_precise_ip_support(struct evlist *evlist, struct evsel *evsel);
#endif
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 1548237b6558..b9c7e5271611 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -9,6 +9,7 @@
#include <errno.h>
#include <inttypes.h>
#include <poll.h>
+#include "arm-spe.h"
#include "cpumap.h"
#include "util/mmap.h"
#include "thread_map.h"
@@ -179,6 +180,7 @@ void perf_evlist__splice_list_tail(struct evlist *evlist,
struct evsel *evsel, *temp;

__evlist__for_each_entry_safe(list, temp, evsel) {
+ arm_spe_precise_ip_support(evlist, evsel);
list_del_init(&evsel->core.node);
evlist__add(evlist, evsel);
}
--
2.17.1