Messages in this thread | | | From | Namhyung Kim <> | Subject | [PATCHSET 0/7] perf lock: New lock contention tracepoints support (v4) | Date | Wed, 15 Jun 2022 09:32:15 -0700 |
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Hello,
Kernel v5.19 will have a new set of tracepoints to track lock contentions for various lock types. Unlike tracepoints in LOCKDEP and LOCK_STAT, it's hit only for contended locks and lock names are not available. So it needs to collect stack traces and display the caller function instead.
Changes in v4) * add Acked-by from Ian * more comments on trace_lock_handler * don't create stats in the contention_end handler
Changes in v3) * fix build error * support data from different kernels/machines * skip bad stat unless there's actual bad ones
Changes in v2) * add Acked-by from Ian * print time with a unit for compact output * add some comments (Ian) * remove already applied patch
This patchset merely adds support for the new tracepoints to the existing perf lock commands. So there's no change to the user. Later I'll add new a sub-command dedicated to the tracepoints to make use of the additional information.
Example output:
$ sudo perf lock record -a sleep 3
$ perf lock report -F acquired,contended,avg_wait,wait_total
Name acquired contended avg wait total wait
update_blocked_a... 40 40 3.61 us 144.45 us kernfs_fop_open+... 5 5 3.64 us 18.18 us _nohz_idle_balance 3 3 2.65 us 7.95 us tick_do_update_j... 1 1 6.04 us 6.04 us ep_scan_ready_list 1 1 3.93 us 3.93 us ...
You can find the code in the 'perf/lock-contention-v4' branch at
git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
Thanks, Namhyung
Namhyung Kim (7): perf lock: Print wait times with unit perf lock: Allow to use different kernel symbols perf lock: Skip print_bad_events() if nothing bad perf lock: Add lock contention tracepoints record support perf lock: Handle lock contention tracepoints perf record: Allow to specify max stack depth of fp callchain perf lock: Look up callchain for the contended locks
tools/perf/Documentation/perf-lock.txt | 7 + tools/perf/Documentation/perf-record.txt | 5 + tools/perf/builtin-lock.c | 426 ++++++++++++++++++++++- tools/perf/util/callchain.c | 18 +- 4 files changed, 434 insertions(+), 22 deletions(-)
base-commit: 9886142c7a2226439c1e3f7d9b69f9c7094c3ef6 -- 2.36.1.476.g0c4daa206d-goog
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