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.
Wang Nan (13):
perf tools: Add overwrite attribute to evsel and check write_backward
perf tools: Record fd into perf_mmap
perf tools: Add API to pause a evlist
perf record: Prevent reading invalid data in record__mmap_read
perf record: Rename variable to make code clear
perf record: Read from backward ring buffer
perf evlist: Introduce aux perf evlist
perf tools: Don't poll and mmap overwritable events
perf tools: Enable overwrite settings
perf record: Introduce rec->overwrite_evlist for overwritable events
perf record: Toggle overwrite ring buffer for reading
perf tools: Don't warn about out of order event if write_backward is
used
perf tools: Check write_backward during evlist config
tools/perf/Documentation/perf-record.txt | 14 ++
tools/perf/arch/x86/util/tsc.c | 2 +
tools/perf/builtin-record.c | 344 +++++++++++++++++++++++++++----
tools/perf/perf.h | 1 +
tools/perf/util/evlist.c | 81 ++++++--
tools/perf/util/evlist.h | 6 +
tools/perf/util/evsel.c | 38 +++-
tools/perf/util/evsel.h | 16 ++
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, 497 insertions(+), 68 deletions(-)
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
--
1.8.3.4
