Messages in this thread Patch in this message |  | | From | Wang Nan <> | Subject | [PATCH 35/55] perf record: Disable buildid cache options by default in switch output mode | Date | Fri, 19 Feb 2016 11:44:23 +0000 |
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Cost of buildid cache processing is high: read all events in output perf.data, open elf files to read buildid then copy them into ~/.debug directory. In switch output mode, causes perf stop receiving from 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> Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com --- tools/perf/builtin-record.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 8987ce8..2839715 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1383,8 +1383,36 @@ 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) { -- 1.8.3.4
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