[PATCH 3/5] perf lock contention: Add -g/--lock-cgroup option
From: Namhyung Kim
Date: Wed Aug 30 2023 - 19:02:01 EST
The -g option shows lock contention stats break down by cgroups.
Add LOCK_AGGR_CGROUP mode and use it instead of use_cgroup field.
$ sudo ./perf lock con -abg sleep 1
contended total wait max wait avg wait cgroup
8 15.70 us 6.34 us 1.96 us /
2 1.48 us 747 ns 738 ns /user.slice/.../app.slice/app-gnome-google\x2dchrome-6442.scope
1 848 ns 848 ns 848 ns /user.slice/.../session.slice/org.gnome.Shell@x11.service
1 220 ns 220 ns 220 ns /user.slice/.../session.slice/pipewire-pulse.service
For now, the cgroup mode only works with BPF (-b).
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/Documentation/perf-lock.txt | 4 ++
tools/perf/builtin-lock.c | 42 ++++++++++++++++++-
tools/perf/util/bpf_lock_contention.c | 14 ++++---
.../perf/util/bpf_skel/lock_contention.bpf.c | 31 +++++++++++++-
tools/perf/util/bpf_skel/lock_data.h | 3 +-
tools/perf/util/lock-contention.h | 1 -
6 files changed, 85 insertions(+), 10 deletions(-)
diff --git a/tools/perf/Documentation/perf-lock.txt b/tools/perf/Documentation/perf-lock.txt
index 30eea576721f..61c491df72b8 100644
--- a/tools/perf/Documentation/perf-lock.txt
+++ b/tools/perf/Documentation/perf-lock.txt
@@ -208,6 +208,10 @@ CONTENTION OPTIONS
Show results using a CSV-style output to make it easy to import directly
into spreadsheets. Columns are separated by the string specified in SEP.
+-g::
+--lock-cgroup::
+ Show lock contention stat by cgroup. Requires --use-bpf.
+
SEE ALSO
--------
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 69086d94f588..b98948dd40ba 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -60,6 +60,7 @@ static bool combine_locks;
static bool show_thread_stats;
static bool show_lock_addrs;
static bool show_lock_owner;
+static bool show_lock_cgroups;
static bool use_bpf;
static unsigned long bpf_map_entries = MAX_ENTRIES;
static int max_stack_depth = CONTENTION_STACK_DEPTH;
@@ -619,6 +620,7 @@ static int get_key_by_aggr_mode_simple(u64 *key, u64 addr, u32 tid)
*key = tid;
break;
case LOCK_AGGR_CALLER:
+ case LOCK_AGGR_CGROUP:
default:
pr_err("Invalid aggregation mode: %d\n", aggr_mode);
return -EINVAL;
@@ -1103,6 +1105,7 @@ static int report_lock_contention_begin_event(struct evsel *evsel,
if (lock_contention_caller(evsel, sample, buf, sizeof(buf)) < 0)
name = "Unknown";
break;
+ case LOCK_AGGR_CGROUP:
case LOCK_AGGR_TASK:
default:
break;
@@ -1653,6 +1656,9 @@ static void print_header_stdio(void)
case LOCK_AGGR_ADDR:
fprintf(lock_output, " %16s %s\n\n", "address", "symbol");
break;
+ case LOCK_AGGR_CGROUP:
+ fprintf(lock_output, " %s\n\n", "cgroup");
+ break;
default:
break;
}
@@ -1680,6 +1686,9 @@ static void print_header_csv(const char *sep)
case LOCK_AGGR_ADDR:
fprintf(lock_output, "%s%s %s%s %s\n", "address", sep, "symbol", sep, "type");
break;
+ case LOCK_AGGR_CGROUP:
+ fprintf(lock_output, "%s\n", "cgroup");
+ break;
default:
break;
}
@@ -1720,6 +1729,9 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
fprintf(lock_output, " %016llx %s (%s)\n", (unsigned long long)st->addr,
st->name, get_type_name(st->flags));
break;
+ case LOCK_AGGR_CGROUP:
+ fprintf(lock_output, " %s\n", st->name);
+ break;
default:
break;
}
@@ -1770,6 +1782,9 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
fprintf(lock_output, "%llx%s %s%s %s\n", (unsigned long long)st->addr, sep,
st->name, sep, get_type_name(st->flags));
break;
+ case LOCK_AGGR_CGROUP:
+ fprintf(lock_output, "%s\n",st->name);
+ break;
default:
break;
}
@@ -1999,6 +2014,27 @@ static int check_lock_contention_options(const struct option *options,
return -1;
}
+ if (show_lock_cgroups && !use_bpf) {
+ pr_err("Cgroups are available only with BPF\n");
+ parse_options_usage(usage, options, "lock-cgroup", 0);
+ parse_options_usage(NULL, options, "use-bpf", 0);
+ return -1;
+ }
+
+ if (show_lock_cgroups && show_lock_addrs) {
+ pr_err("Cannot use cgroup and addr mode together\n");
+ parse_options_usage(usage, options, "lock-cgroup", 0);
+ parse_options_usage(NULL, options, "lock-addr", 0);
+ return -1;
+ }
+
+ if (show_lock_cgroups && show_thread_stats) {
+ pr_err("Cannot use cgroup and thread mode together\n");
+ parse_options_usage(usage, options, "lock-cgroup", 0);
+ parse_options_usage(NULL, options, "threads", 0);
+ return -1;
+ }
+
if (symbol_conf.field_sep) {
if (strstr(symbol_conf.field_sep, ":") || /* part of type flags */
strstr(symbol_conf.field_sep, "+") || /* part of caller offset */
@@ -2060,7 +2096,8 @@ static int __cmd_contention(int argc, const char **argv)
con.machine = &session->machines.host;
con.aggr_mode = aggr_mode = show_thread_stats ? LOCK_AGGR_TASK :
- show_lock_addrs ? LOCK_AGGR_ADDR : LOCK_AGGR_CALLER;
+ show_lock_addrs ? LOCK_AGGR_ADDR :
+ show_lock_cgroups ? LOCK_AGGR_CGROUP : LOCK_AGGR_CALLER;
if (con.aggr_mode == LOCK_AGGR_CALLER)
con.save_callstack = true;
@@ -2159,7 +2196,7 @@ static int __cmd_contention(int argc, const char **argv)
out_delete:
lock_filter_finish();
evlist__delete(con.evlist);
- lock_contention_finish();
+ lock_contention_finish(&con);
perf_session__delete(session);
zfree(&lockhash_table);
return err;
@@ -2524,6 +2561,7 @@ int cmd_lock(int argc, const char **argv)
OPT_BOOLEAN('o', "lock-owner", &show_lock_owner, "show lock owners instead of waiters"),
OPT_STRING_NOEMPTY('x', "field-separator", &symbol_conf.field_sep, "separator",
"print result in CSV format with custom separator"),
+ OPT_BOOLEAN('g', "lock-cgroup", &show_lock_cgroups, "show lock stats by cgroup"),
OPT_PARENT(lock_options)
};
diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index 9d36b07eccf5..42753a0dfdc5 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -152,7 +152,10 @@ int lock_contention_prepare(struct lock_contention *con)
skel->bss->needs_callstack = con->save_callstack;
skel->bss->lock_owner = con->owner;
- if (con->use_cgroup) {
+ if (con->aggr_mode == LOCK_AGGR_CGROUP) {
+ if (cgroup_is_v2("perf_event"))
+ skel->bss->use_cgroup_v2 = 1;
+
read_all_cgroups(&con->cgroups);
}
@@ -214,12 +217,12 @@ static const char *lock_contention_get_name(struct lock_contention *con,
return "siglock";
/* global locks with symbols */
- sym = machine__find_kernel_symbol(machine, key->lock_addr, &kmap);
+ sym = machine__find_kernel_symbol(machine, key->lock_addr_or_cgroup, &kmap);
if (sym)
return sym->name;
/* try semi-global locks collected separately */
- if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr, &flags)) {
+ if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr_or_cgroup, &flags)) {
if (flags == LOCK_CLASS_RQLOCK)
return "rq_lock";
}
@@ -227,7 +230,7 @@ static const char *lock_contention_get_name(struct lock_contention *con,
return "";
}
- if (con->use_cgroup) {
+ if (con->aggr_mode == LOCK_AGGR_CGROUP) {
u64 cgrp_id = key->lock_addr_or_cgroup;
struct cgroup *cgrp = __cgroup__find(&con->cgroups, cgrp_id);
@@ -329,7 +332,8 @@ int lock_contention_read(struct lock_contention *con)
ls_key = key.pid;
break;
case LOCK_AGGR_ADDR:
- ls_key = key.lock_addr;
+ case LOCK_AGGR_CGROUP:
+ ls_key = key.lock_addr_or_cgroup;
break;
default:
goto next;
diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
index 8d3cfbb3cc65..823354999022 100644
--- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
+++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
@@ -118,6 +118,9 @@ int needs_callstack;
int stack_skip;
int lock_owner;
+int use_cgroup_v2;
+int perf_subsys_id = -1;
+
/* determine the key of lock stat */
int aggr_mode;
@@ -130,6 +133,29 @@ int data_fail;
int task_map_full;
int data_map_full;
+static inline __u64 get_current_cgroup_id(void)
+{
+ struct task_struct *task;
+ struct cgroup *cgrp;
+
+ if (use_cgroup_v2)
+ return bpf_get_current_cgroup_id();
+
+ task = bpf_get_current_task_btf();
+
+ if (perf_subsys_id == -1) {
+#if __has_builtin(__builtin_preserve_enum_value)
+ perf_subsys_id = bpf_core_enum_value(enum cgroup_subsys_id,
+ perf_event_cgrp_id);
+#else
+ perf_subsys_id = perf_event_cgrp_id;
+#endif
+ }
+
+ cgrp = BPF_CORE_READ(task, cgroups, subsys[perf_subsys_id], cgroup);
+ return BPF_CORE_READ(cgrp, kn, id);
+}
+
static inline int can_record(u64 *ctx)
{
if (has_cpu) {
@@ -364,10 +390,13 @@ int contention_end(u64 *ctx)
key.stack_id = pelem->stack_id;
break;
case LOCK_AGGR_ADDR:
- key.lock_addr = pelem->lock;
+ key.lock_addr_or_cgroup = pelem->lock;
if (needs_callstack)
key.stack_id = pelem->stack_id;
break;
+ case LOCK_AGGR_CGROUP:
+ key.lock_addr_or_cgroup = get_current_cgroup_id();
+ break;
default:
/* should not happen */
return 0;
diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_skel/lock_data.h
index 260062a9f2ab..08482daf61be 100644
--- a/tools/perf/util/bpf_skel/lock_data.h
+++ b/tools/perf/util/bpf_skel/lock_data.h
@@ -6,7 +6,7 @@
struct contention_key {
u32 stack_id;
u32 pid;
- u64 lock_addr;
+ u64 lock_addr_or_cgroup;
};
#define TASK_COMM_LEN 16
@@ -39,6 +39,7 @@ enum lock_aggr_mode {
LOCK_AGGR_ADDR = 0,
LOCK_AGGR_TASK,
LOCK_AGGR_CALLER,
+ LOCK_AGGR_CGROUP,
};
enum lock_class_sym {
diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h
index 70423966d778..a073cc6a82d2 100644
--- a/tools/perf/util/lock-contention.h
+++ b/tools/perf/util/lock-contention.h
@@ -144,7 +144,6 @@ struct lock_contention {
int owner;
int nr_filtered;
bool save_callstack;
- bool use_cgroup;
};
#ifdef HAVE_BPF_SKEL
--
2.42.0.283.g2d96d420d3-goog