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Date: Wed, 7 Sep 2022 23:37:52 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jiri Olsa <jolsa@...nel.org>
Cc: Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
LKML <linux-kernel@...r.kernel.org>,
Ian Rogers <irogers@...gle.com>,
linux-perf-users@...r.kernel.org, Song Liu <songliubraving@...com>,
bpf@...r.kernel.org
Subject: [PATCH 2/4] perf lock contention: Show full callstack with -v option
Currently it shows a caller function for each entry, but users need to see
the full call stacks sometimes. Use -v/--verbose option to do that.
# perf lock con -a -b -v sleep 3
Looking at the vmlinux_path (8 entries long)
symsrc__init: cannot get elf header.
Using /proc/kcore for kernel data
Using /proc/kallsyms for symbols
contended total wait max wait avg wait type caller
1 10.74 us 10.74 us 10.74 us spinlock __bpf_trace_contention_begin+0xb
0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
0xffffffffbb8b8e75 bpf_trace_run2+0x35
0xffffffffbb7eab9b __bpf_trace_contention_begin+0xb
0xffffffffbb7ebe75 queued_spin_lock_slowpath+0x1f5
0xffffffffbc1c26ff _raw_spin_lock+0x1f
0xffffffffbb841015 tick_do_update_jiffies64+0x25
0xffffffffbb8409ee tick_irq_enter+0x9e
1 7.70 us 7.70 us 7.70 us spinlock __bpf_trace_contention_begin+0xb
0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
0xffffffffbb8b8e75 bpf_trace_run2+0x35
0xffffffffbb7eab9b __bpf_trace_contention_begin+0xb
0xffffffffbb7ebe75 queued_spin_lock_slowpath+0x1f5
0xffffffffbc1c26ff _raw_spin_lock+0x1f
0xffffffffbb7bc27e raw_spin_rq_lock_nested+0xe
0xffffffffbb7cef9c load_balance+0x66c
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/builtin-lock.c | 43 ++++++++++++++++++++++-----
tools/perf/util/bpf_lock_contention.c | 9 ++++++
tools/perf/util/lock-contention.h | 1 +
3 files changed, 46 insertions(+), 7 deletions(-)
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 2a5672f8d22e..e66fbb38d8df 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -972,13 +972,14 @@ static int lock_contention_caller(struct evsel *evsel, struct perf_sample *sampl
return -1;
}
-static u64 callchain_id(struct evsel *evsel, struct perf_sample *sample)
+static u64 callchain_id(struct evsel *evsel, struct perf_sample *sample, u64 *callchains)
{
struct callchain_cursor *cursor = &callchain_cursor;
struct machine *machine = &session->machines.host;
struct thread *thread;
u64 hash = 0;
int skip = 0;
+ int i = 0;
int ret;
thread = machine__findnew_thread(machine, -1, sample->pid);
@@ -1002,6 +1003,9 @@ static u64 callchain_id(struct evsel *evsel, struct perf_sample *sample)
if (node == NULL)
break;
+ if (callchains)
+ callchains[i++] = node->ip;
+
/* skip first few entries - for lock functions */
if (++skip <= CONTENTION_STACK_SKIP)
goto next;
@@ -1025,6 +1029,7 @@ static int report_lock_contention_begin_event(struct evsel *evsel,
struct lock_seq_stat *seq;
u64 addr = evsel__intval(evsel, sample, "lock_addr");
u64 key;
+ u64 callchains[CONTENTION_STACK_DEPTH];
switch (aggr_mode) {
case LOCK_AGGR_ADDR:
@@ -1034,7 +1039,9 @@ static int report_lock_contention_begin_event(struct evsel *evsel,
key = sample->tid;
break;
case LOCK_AGGR_CALLER:
- key = callchain_id(evsel, sample);
+ if (verbose)
+ memset(callchains, 0, sizeof(callchains));
+ key = callchain_id(evsel, sample, verbose ? callchains : NULL);
break;
default:
pr_err("Invalid aggregation mode: %d\n", aggr_mode);
@@ -1053,6 +1060,12 @@ static int report_lock_contention_begin_event(struct evsel *evsel,
ls = lock_stat_findnew(key, caller, flags);
if (!ls)
return -ENOMEM;
+
+ if (aggr_mode == LOCK_AGGR_CALLER && verbose) {
+ ls->callstack = memdup(callchains, sizeof(callchains));
+ if (ls->callstack == NULL)
+ return -ENOMEM;
+ }
}
ts = thread_stat_findnew(sample->tid);
@@ -1117,7 +1130,7 @@ static int report_lock_contention_end_event(struct evsel *evsel,
key = sample->tid;
break;
case LOCK_AGGR_CALLER:
- key = callchain_id(evsel, sample);
+ key = callchain_id(evsel, sample, NULL);
break;
default:
pr_err("Invalid aggregation mode: %d\n", aggr_mode);
@@ -1466,7 +1479,7 @@ static void sort_contention_result(void)
sort_result();
}
-static void print_contention_result(void)
+static void print_contention_result(struct lock_contention *con)
{
struct lock_stat *st;
struct lock_key *key;
@@ -1505,6 +1518,22 @@ static void print_contention_result(void)
}
pr_info(" %10s %s\n", get_type_str(st), st->name);
+ if (verbose) {
+ struct map *kmap;
+ struct symbol *sym;
+ char buf[128];
+ u64 ip;
+
+ for (int i = 0; i < CONTENTION_STACK_DEPTH; i++) {
+ if (!st->callstack || !st->callstack[i])
+ break;
+
+ ip = st->callstack[i];
+ sym = machine__find_kernel_symbol(con->machine, ip, &kmap);
+ get_symbol_name_offset(kmap, sym, ip, buf, sizeof(buf));
+ pr_info("\t\t\t%#lx %s\n", (unsigned long)ip, buf);
+ }
+ }
}
print_bad_events(bad, total);
@@ -1620,6 +1649,8 @@ static int __cmd_contention(int argc, const char **argv)
return PTR_ERR(session);
}
+ con.machine = &session->machines.host;
+
/* for lock function check */
symbol_conf.sort_by_name = true;
symbol__init(&session->header.env);
@@ -1638,8 +1669,6 @@ static int __cmd_contention(int argc, const char **argv)
signal(SIGCHLD, sighandler);
signal(SIGTERM, sighandler);
- con.machine = &session->machines.host;
-
con.evlist = evlist__new();
if (con.evlist == NULL) {
err = -ENOMEM;
@@ -1711,7 +1740,7 @@ static int __cmd_contention(int argc, const char **argv)
setup_pager();
sort_contention_result();
- print_contention_result();
+ print_contention_result(&con);
out_delete:
evlist__delete(con.evlist);
diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index c591a66733ef..6545bee65347 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -8,6 +8,7 @@
#include "util/thread_map.h"
#include "util/lock-contention.h"
#include <linux/zalloc.h>
+#include <linux/string.h>
#include <bpf/bpf.h>
#include "bpf_skel/lock_contention.skel.h"
@@ -171,6 +172,14 @@ int lock_contention_read(struct lock_contention *con)
return -1;
}
+ if (verbose) {
+ st->callstack = memdup(stack_trace, sizeof(stack_trace));
+ if (st->callstack == NULL) {
+ free(st);
+ return -1;
+ }
+ }
+
hlist_add_head(&st->hash_entry, con->result);
prev_key = key;
}
diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h
index 2146efc33396..bdb6e2a61e5b 100644
--- a/tools/perf/util/lock-contention.h
+++ b/tools/perf/util/lock-contention.h
@@ -11,6 +11,7 @@ struct lock_stat {
u64 addr; /* address of lockdep_map, used as ID */
char *name; /* for strcpy(), we cannot use const */
+ u64 *callstack;
unsigned int nr_acquire;
unsigned int nr_acquired;
--
2.37.2.789.g6183377224-goog
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