Hi Ian,
On Wed, Jun 04, 2025 at 10:45:34AM -0700, Ian Rogers wrote:
> Rather than scanning /proc and skipping PIDs based on their UIDs, use
> BPF filters for uid filtering. The /proc scanning in thread_map is
> racy as the PID may exit before the perf_event_open causing perf to
> abort. BPF UID filters are more robust as they avoid the race. The
> /proc scanning also misses processes starting after the perf
> command. Add a helper for commands that support UID filtering and wire
> up. Remove the non-BPF UID filtering support given it doesn't work.
>
> v4: Add a warning message on top of Namhyung's BPF filter error message:
> https://lore.kernel.org/lkml/20250604054234.23608-1-namhyung@kernel.org/
> in the parse_uid_filter helper. In TUI the warning is shown then
> the BPF error shown, with stdio the warning appears below the BPF
> errors.
>
> v3: Add lengthier commit messages as requested by Arnaldo. Rebase on
> tmp.perf-tools-next.
>
> v2: Add a perf record uid test (Namhyung) and force setting
> system-wide for perf trace and perf record (Namhyung). Ensure the
> uid filter isn't set on tracepoint evsels.
>
> v1: https://lore.kernel.org/lkml/20250111190143.1029906-1-irogers@google.com/
>
> Ian Rogers (10):
> perf parse-events filter: Use evsel__find_pmu
> perf target: Separate parse_uid into its own function
> perf parse-events: Add parse_uid_filter helper
> perf record: Switch user option to use BPF filter
> perf tests record: Add basic uid filtering test
> perf top: Switch user option to use BPF filter
> perf trace: Switch user option to use BPF filter
> perf bench evlist-open-close: Switch user option to use BPF filter
> perf target: Remove uid from target
> perf thread_map: Remove uid options
I've noticed two things.
* it takes a quite long time to load the BPF filter. Not sure what's
the issue, but maybe annoying for users.
* normal users cannot use BPF filter even if the BPF is loaded and
pinned already. It works fine for perf record.
I don't think the issues are from this change though.
Thanks,
Namhyung
>
> tools/perf/bench/evlist-open-close.c | 36 ++++++++------
> tools/perf/builtin-ftrace.c | 1 -
> tools/perf/builtin-kvm.c | 2 -
> tools/perf/builtin-record.c | 27 ++++++-----
> tools/perf/builtin-stat.c | 4 +-
> tools/perf/builtin-top.c | 22 +++++----
> tools/perf/builtin-trace.c | 27 +++++++----
> tools/perf/tests/backward-ring-buffer.c | 1 -
> tools/perf/tests/event-times.c | 8 ++-
> tools/perf/tests/keep-tracking.c | 2 +-
> tools/perf/tests/mmap-basic.c | 2 +-
> tools/perf/tests/openat-syscall-all-cpus.c | 2 +-
> tools/perf/tests/openat-syscall-tp-fields.c | 1 -
> tools/perf/tests/openat-syscall.c | 2 +-
> tools/perf/tests/perf-record.c | 1 -
> tools/perf/tests/perf-time-to-tsc.c | 2 +-
> tools/perf/tests/shell/record.sh | 26 ++++++++++
> tools/perf/tests/switch-tracking.c | 2 +-
> tools/perf/tests/task-exit.c | 1 -
> tools/perf/tests/thread-map.c | 2 +-
> tools/perf/util/bpf-filter.c | 2 +-
> tools/perf/util/evlist.c | 3 +-
> tools/perf/util/parse-events.c | 47 +++++++++++++-----
> tools/perf/util/parse-events.h | 1 +
> tools/perf/util/python.c | 10 ++--
> tools/perf/util/target.c | 54 +++------------------
> tools/perf/util/target.h | 15 ++----
> tools/perf/util/thread_map.c | 32 ++----------
> tools/perf/util/thread_map.h | 6 +--
> tools/perf/util/top.c | 4 +-
> tools/perf/util/top.h | 1 +
> 31 files changed, 164 insertions(+), 182 deletions(-)
>
> --
> 2.50.0.rc0.604.gd4ff7b7c86-goog
>