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Diffstat (limited to 'tools/perf/Documentation/perf-record.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-record.txt | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 8dbee832abd9..69966abf65d1 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -360,6 +360,35 @@ particular perf.data snapshot should be kept or not. Implies --timestamp-filename, --no-buildid and --no-buildid-cache. +--dry-run:: +Parse options then exit. --dry-run can be used to detect errors in cmdline +options. + +'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj +in config file is set to true. + +--tail-synthesize:: +Instead of collecting non-sample events (for example, fork, comm, mmap) at +the beginning of record, collect them during finalizing an output file. +The collected non-sample events reflects the status of the system when +record is finished. + +--overwrite:: +Makes all events use an overwritable ring buffer. An overwritable ring +buffer works like a flight recorder: when it gets full, the kernel will +overwrite the oldest records, that thus will never make it to the +perf.data file. + +When '--overwrite' and '--switch-output' are used perf records and drops +events until it receives a signal, meaning that something unusual was +detected that warrants taking a snapshot of the most current events, +those fitting in the ring buffer at that moment. + +'overwrite' attribute can also be set or canceled for an event using +config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'. + +Implies --tail-synthesize. + SEE ALSO -------- linkperf:perf-stat[1], linkperf:perf-list[1] |