linux-kernel - [PATCH v3 5/5] perf lock: Update documentation for -o option in contention mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250129001905.619859-6-ctshao@google.com>
Date: Tue, 28 Jan 2025 16:15:01 -0800
From: Chun-Tse Shao <ctshao@...gle.com>
To: linux-kernel@...r.kernel.org
Cc: Chun-Tse Shao <ctshao@...gle.com>, peterz@...radead.org, mingo@...hat.com, 
	acme@...nel.org, namhyung@...nel.org, mark.rutland@....com, 
	alexander.shishkin@...ux.intel.com, jolsa@...nel.org, irogers@...gle.com, 
	adrian.hunter@...el.com, kan.liang@...ux.intel.com, nathan@...nel.org, 
	ndesaulniers@...gle.com, morbo@...gle.com, justinstitt@...gle.com, 
	linux-perf-users@...r.kernel.org, bpf@...r.kernel.org, llvm@...ts.linux.dev
Subject: [PATCH v3 5/5] perf lock: Update documentation for -o option in
 contention mode

This patch also decouple -o with -t, and shows warning to notify the new
behavior for -ov.

Signed-off-by: Chun-Tse Shao <ctshao@...gle.com>
---
 tools/perf/builtin-lock.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index d9b0d7472aea..b925be06b0d8 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -1818,7 +1818,7 @@ static void print_contention_result(struct lock_contention *con)
 			break;
 	}
 
-	if (con->owner && con->save_callstack) {
+	if (con->owner && con->save_callstack && verbose > 0) {
 		struct rb_root root = RB_ROOT;
 
 		if (symbol_conf.field_sep)
@@ -1979,6 +1979,11 @@ static int check_lock_contention_options(const struct option *options,
 		}
 	}
 
+	if (show_lock_owner && !show_thread_stats) {
+		pr_warning("Now -o try to show owner's callstack instead of pid and comm.\n");
+		pr_warning("Please use -t option too to keep the old behavior.\n");
+	}
+
 	return 0;
 }
 
@@ -2570,7 +2575,8 @@ int cmd_lock(int argc, const char **argv)
 		     "Filter specific address/symbol of locks", parse_lock_addr),
 	OPT_CALLBACK('S', "callstack-filter", NULL, "NAMES",
 		     "Filter specific function in the callstack", parse_call_stack),
-	OPT_BOOLEAN('o', "lock-owner", &show_lock_owner, "show lock owners instead of waiters"),
+	OPT_BOOLEAN('o', "lock-owner", &show_lock_owner, "show lock owners instead of waiters.\n"
+		"\t\t\tThis option can be combined with -t, which shows owner's per thread lock stats, or -v, which shows owner's stacktrace"),
 	OPT_STRING_NOEMPTY('x', "field-separator", &symbol_conf.field_sep, "separator",
 		   "print result in CSV format with custom separator"),
 	OPT_BOOLEAN(0, "lock-cgroup", &show_lock_cgroups, "show lock stats by cgroup"),
-- 
2.48.1.262.g85cc9f2d1e-goog