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![]() In addition to the function latency, it can measure events latencies. Some kernel tracepoints are paired and it's menningful to measure how long it takes between the two events. The latency is tracked for the same thread. Currently it only uses BPF to do the work but it can be lifted later. Instead of having separate a BPF program for each tracepoint, it only uses generic 'event_begin' and 'event_end' programs to attach to any (raw) tracepoints. $ sudo perf ftrace latency -a -b --hide-empty \ -e i915_request_wait_begin,i915_request_wait_end -- sleep 1 # DURATION | COUNT | GRAPH | 256 - 512 us | 4 | ###### | 2 - 4 ms | 2 | ### | 4 - 8 ms | 12 | ################### | 8 - 16 ms | 10 | ################ | # statistics (in usec) total time: 194915 avg time: 6961 max time: 12855 min time: 373 count: 28 Reviewed-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20250714052143.342851-1-namhyung@kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> |
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.. | ||
vmlinux | ||
.gitignore | ||
augmented_raw_syscalls.bpf.c | ||
bench_uprobe.bpf.c | ||
bperf_cgroup.bpf.c | ||
bperf_follower.bpf.c | ||
bperf_leader.bpf.c | ||
bperf_u.h | ||
bpf_prog_profiler.bpf.c | ||
func_latency.bpf.c | ||
kwork_top.bpf.c | ||
kwork_trace.bpf.c | ||
lock_contention.bpf.c | ||
lock_data.h | ||
off_cpu.bpf.c | ||
perf_version.h | ||
sample-filter.h | ||
sample_filter.bpf.c | ||
syscall_summary.bpf.c | ||
syscall_summary.h |