This patch set enables daemonized perf recording by utilizing overwritable backward ring buffer. With this feature one can put perf background, and dump ring buffer records by a SIGUSR2 when he/she find something unusual. For example, following command record system calls, schedule events and samples on cpu cycles continously:
# perf record -g -e cycles -e raw_syscalls:*/call-graph=no/ \ -e sched:sched_switch/call-graph=no/ \ --switch-output --overwrite -a Then by sending SIGUSR2 to perf when lagging is happen, we get multiple perf.data output, each of them correspond a abnormal event, and the data size is reasonable: # ls -l ./perf.data* -rw------- 1 root root 5122165 May 13 23:51 ./perf.data.2016051323511683 -rw------- 1 root root 5135093 May 13 23:51 ./perf.data.2016051323512107 -rw------- 1 root root 5135213 May 13 23:51 ./perf.data.2016051323512215 -rw------- 1 root root 5135157 May 13 23:51 ./perf.data.2016051323512387 v1 -> v2: Totally redesign: drop the principle of 'channal', use auxiliary evlist instead. Fix missing documentation. v2 -> v3: Rename perf_evlist__toggle_paused() to perf_evlist__pause/resume. v3 -> v4: Update commit message to describe auxiliary evlist more clearly. v4 -> v5: Reorder commits, ensure '--overwrite' works right after perf support the option. Add test cases for auxiliary evlist. Avoid bug if main evlist is empty. v5 -> v6: Improve filter pollfd related code. v6 -> v7: Rebase to newest perf/core. Wang Nan (8): perf evlist: Introduce aux evlist perf tests: Add testcase for auxiliary evlist perf record: Introduce rec->overwrite_evlist for overwritable events perf record: Toggle overwrite ring buffer for reading perf tools: Enable overwrite settings perf tools: Don't warn about out of order event if write_backward is used perf tools: Check write_backward during evlist config perf record: Unmap overwrite evlist when event terminate tools/perf/Documentation/perf-record.txt | 14 ++ tools/perf/builtin-record.c | 301 +++++++++++++++++++++++++++---- tools/perf/perf.h | 1 + tools/perf/tests/backward-ring-buffer.c | 86 +++++++-- tools/perf/util/evlist.c | 34 ++-- tools/perf/util/evlist.h | 5 +- tools/perf/util/evsel.c | 27 +-- tools/perf/util/evsel.h | 15 ++ tools/perf/util/parse-events.c | 20 +- tools/perf/util/parse-events.h | 2 + tools/perf/util/parse-events.l | 2 + tools/perf/util/record.c | 17 ++ tools/perf/util/session.c | 22 ++- 13 files changed, 463 insertions(+), 83 deletions(-) -- 1.8.3.4