Hi folks,
In the context of CPU isolation / NOHZ_FULL interference investigation, we now
have the ipi_send_cpu and ipi_send_cpumask events. However, enabling these
events without any filtering can yield pretty massive traces with a lot of
uninteresting or irrelevant data (e.g. everything targeting housekeeping CPUs).
This series is about adding event filtering via a user-provided cpumask. This
enables filtering using cpumask fields (e.g. ipi_send_cpumask) and extends this
to scalar and the local CPU common fields.
With this, it becomes fairly easy to trace events both happening on and
targeting CPUs of interest, e.g.:
trace-cmd record -e 'sched_switch' -f "CPU & MASK{$ISOLATED_CPUS}" \
-e 'sched_wakeup' -f "target_cpu & MASK{$ISOLATED_CPUS}" \
-e 'ipi_send_cpu' -f "cpu & MASK{$ISOLATED_CPUS}" \
-e 'ipi_send_cpumask' -f "cpumask & MASK{$ISOLATED_CPUS}" \
hackbench
The MASK{} thing is a bit crude but seems to work well enough without break^C
overhauling the predicate parsing logic.
Cheers,
Valentin
Valentin Schneider (5):
tracing/filters: Dynamically allocate filter_pred.regex
tracing/filters: Enable filtering a cpumask field by another cpumask
tracing/filters: Enable filtering a scalar field by a cpumask
tracing/filters: Enable filtering the CPU common field by a cpumask
tracing/filters: Document cpumask filtering
Documentation/trace/events.rst | 14 ++
include/linux/trace_events.h | 1 +
kernel/trace/trace_events_filter.c | 228 +++++++++++++++++++++++++----
3 files changed, 216 insertions(+), 27 deletions(-)
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2.31.1
