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Subject[PATCH v2 2/3] perf lock: Add --map-nr-entries option
Date
The --map-nr-entries option is to control number of max entries in the
perf lock contention BPF maps.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/Documentation/perf-lock.txt | 3 +++
tools/perf/builtin-lock.c | 23 ++++++++++++++++++++++-
tools/perf/util/bpf_lock_contention.c | 3 +++
tools/perf/util/lock-contention.h | 1 +
4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-lock.txt b/tools/perf/Documentation/perf-lock.txt
index 7949d2e6891b..193c5d8b8db9 100644
--- a/tools/perf/Documentation/perf-lock.txt
+++ b/tools/perf/Documentation/perf-lock.txt
@@ -145,6 +145,9 @@ CONTENTION OPTIONS
--tid=::
Record events on existing thread ID (comma separated list).

+--map-nr-entries::
+ Maximum number of BPF map entries (default: 10240).
+

SEE ALSO
--------
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index eef778b7d33d..4c70cd1b9006 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -55,6 +55,7 @@ static struct rb_root thread_stats;
static bool combine_locks;
static bool show_thread_stats;
static bool use_bpf;
+static unsigned long bpf_map_entries = 10240;

static enum {
LOCK_AGGR_ADDR,
@@ -1597,6 +1598,7 @@ static int __cmd_contention(int argc, const char **argv)
struct lock_contention con = {
.target = &target,
.result = &lockhash_table[0],
+ .map_nr_entries = bpf_map_entries,
};

session = perf_session__new(use_bpf ? NULL : &data, &eops);
@@ -1786,6 +1788,24 @@ static int __cmd_record(int argc, const char **argv)
return ret;
}

+static int parse_map_entry(const struct option *opt, const char *str,
+ int unset __maybe_unused)
+{
+ unsigned long *len = (unsigned long *)opt->value;
+ unsigned long val;
+ char *endptr;
+
+ errno = 0;
+ val = strtoul(str, &endptr, 0);
+ if (*endptr != '\0' || errno != 0) {
+ pr_err("invalid BPF map length: %s\n", str);
+ return -1;
+ }
+
+ *len = val;
+ return 0;
+}
+
int cmd_lock(int argc, const char **argv)
{
const struct option lock_options[] = {
@@ -1835,9 +1855,10 @@ int cmd_lock(int argc, const char **argv)
"List of cpus to monitor"),
OPT_STRING('p', "pid", &target.pid, "pid",
"Trace on existing process id"),
- /* TODO: Add short option -t after -t/--tracer can be removed. */
OPT_STRING(0, "tid", &target.tid, "tid",
"Trace on existing thread id (exclusive to --pid)"),
+ OPT_CALLBACK(0, "map-nr-entries", &bpf_map_entries, "num",
+ "Max number of BPF map entries", parse_map_entry),
OPT_PARENT(lock_options)
};

diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index f5e2b4f19a72..0556cf4469ff 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -40,6 +40,9 @@ int lock_contention_prepare(struct lock_contention *con)
return -1;
}

+ bpf_map__set_max_entries(skel->maps.stacks, con->map_nr_entries);
+ bpf_map__set_max_entries(skel->maps.lock_stat, con->map_nr_entries);
+
if (target__has_cpu(target))
ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
if (target__has_task(target))
diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h
index a0df5308cca4..8de8550f5ef8 100644
--- a/tools/perf/util/lock-contention.h
+++ b/tools/perf/util/lock-contention.h
@@ -112,6 +112,7 @@ struct lock_contention {
struct target *target;
struct machine *machine;
struct hlist_head *result;
+ unsigned long map_nr_entries;
};

#ifdef HAVE_BPF_SKEL
--
2.37.1.455.g008518b4e5-goog
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