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Diffstat (limited to 'tools/perf/Documentation/perf-record.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-record.txt | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 5b46b1d..384c630 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -367,6 +367,20 @@ options. 'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj in config file is set to true. +--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/'. + SEE ALSO -------- linkperf:perf-stat[1], linkperf:perf-list[1] |