diff options
| author | Wang Nan <wangnan0@huawei.com> | 2016-04-20 18:59:52 +0000 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-04-28 09:58:59 -0300 |
| commit | 0c1d46a8796e8309f1ca693e5cad6f318e4b8159 (patch) | |
| tree | 498eda9d8a2a2164bcfe409813fe44df2501d1a3 /tools | |
| parent | eca857ab381858450ec2f91f5aaae7f2f7a7a180 (diff) | |
| download | linux-0c1d46a8796e8309f1ca693e5cad6f318e4b8159.tar.bz2 | |
perf record: Disable buildid cache options by default in switch output mode
The cost of buildid cache processing is high: reading all events in
output perf.data, opening each elf file to read buildids then copying
them into ~/.debug directory. In switch output mode, these heavy works
block perf from receiving perf events for too long.
Enable no-buildid and no-buildid-cache by default if --switch-output is
provided. Still allow user use --no-no-buildid to explicitly enable
buildid in this case.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1461178794-40467-6-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
[ Updated man page ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/Documentation/perf-record.txt | 2 | ||||
| -rw-r--r-- | tools/perf/builtin-record.c | 30 |
2 files changed, 30 insertions, 2 deletions
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 79a8a14f37b1..8dbee832abd9 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -358,7 +358,7 @@ A possible use case is to, given an external event, slice the perf.data file that gets then processed, possibly via a perf script, to decide if that particular perf.data snapshot should be kept or not. -Implies --timestamp-filename. +Implies --timestamp-filename, --no-buildid and --no-buildid-cache. SEE ALSO -------- diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 80b805b7f5c7..178b49ecd05f 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1387,8 +1387,36 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused) "If some relocation was applied (e.g. kexec) symbols may be misresolved\n" "even with a suitable vmlinux or kallsyms file.\n\n"); - if (rec->no_buildid_cache || rec->no_buildid) + if (rec->no_buildid_cache || rec->no_buildid) { disable_buildid_cache(); + } else if (rec->switch_output) { + /* + * In 'perf record --switch-output', disable buildid + * generation by default to reduce data file switching + * overhead. Still generate buildid if they are required + * explicitly using + * + * perf record --signal-trigger --no-no-buildid \ + * --no-no-buildid-cache + * + * Following code equals to: + * + * if ((rec->no_buildid || !rec->no_buildid_set) && + * (rec->no_buildid_cache || !rec->no_buildid_cache_set)) + * disable_buildid_cache(); + */ + bool disable = true; + + if (rec->no_buildid_set && !rec->no_buildid) + disable = false; + if (rec->no_buildid_cache_set && !rec->no_buildid_cache) + disable = false; + if (disable) { + rec->no_buildid = true; + rec->no_buildid_cache = true; + disable_buildid_cache(); + } + } if (rec->evlist->nr_entries == 0 && perf_evlist__add_default(rec->evlist) < 0) { |