From a1ac1d3c085420ea8c809ebbee3bb212ed3616bd Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Thu, 17 Jun 2010 11:39:01 +0200 Subject: [PATCH] perf record: Add option to avoid updating buildid cache MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There are situations where there is enough information in the perf.data to process the samples. Updating the buildid cache may add unecessary overhead in terms of disk space and time (copying large elf images). A persistent option to do this already exists via the perfconfig file, simply do: [buildid] dir = /dev/null This patch provides a way to suppress builid cache updates on a per-run basis. It addds a new option, -N, to perf record. Buildids are still generated in the perf.data file. Cc: David S. Miller Cc: Frédéric Weisbecker Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra LKML-Reference: <4c19ef89.93ecd80a.40dc.fffff8e9@mx.google.com> Signed-off-by: Stephane Eranian Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-record.txt | 6 ++++++ tools/perf/builtin-record.c | 5 +++++ tools/perf/util/header.c | 10 +++++++++- tools/perf/util/util.h | 1 + 4 files changed, 21 insertions(+), 1 deletion(-) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 25576b477c83..3ee27dccfde9 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -110,6 +110,12 @@ comma-sperated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2 In per-thread mode with inheritance mode on (default), samples are captured only when the thread executes on the designated CPUs. Default is to monitor all CPUs. +-N:: +--no-buildid-cache:: +Do not update the builid cache. This saves some overhead in situations +where the information in the perf.data file (which includes buildids) +is sufficient. + SEE ALSO -------- linkperf:perf-stat[1], linkperf:perf-list[1] diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 5efc3fc68a36..86b1c3b6264e 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -60,6 +60,7 @@ static bool call_graph = false; static bool inherit_stat = false; static bool no_samples = false; static bool sample_address = false; +static bool no_buildid = false; static long samples = 0; static u64 bytes_written = 0; @@ -825,6 +826,8 @@ static const struct option options[] = { "Sample addresses"), OPT_BOOLEAN('n', "no-samples", &no_samples, "don't sample"), + OPT_BOOLEAN('N', "no-buildid-cache", &no_buildid, + "do not update the buildid cache"), OPT_END() }; @@ -849,6 +852,8 @@ int cmd_record(int argc, const char **argv, const char *prefix __used) } symbol__init(); + if (no_buildid) + disable_buildid_cache(); if (!nr_counters) { nr_counters = 1; diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 4a6a4b3a4ab7..d7e67b167ea3 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -16,6 +16,8 @@ #include "symbol.h" #include "debug.h" +static bool no_buildid_cache = false; + /* * Create new perf.data header attribute: */ @@ -470,7 +472,8 @@ static int perf_header__adds_write(struct perf_header *self, int fd) } buildid_sec->size = lseek(fd, 0, SEEK_CUR) - buildid_sec->offset; - perf_session__cache_build_ids(session); + if (!no_buildid_cache) + perf_session__cache_build_ids(session); } lseek(fd, sec_start, SEEK_SET); @@ -1189,3 +1192,8 @@ int event__process_build_id(event_t *self, session); return 0; } + +void disable_buildid_cache(void) +{ + no_buildid_cache = true; +} diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h index de61441b6dd7..f380fed74359 100644 --- a/tools/perf/util/util.h +++ b/tools/perf/util/util.h @@ -154,6 +154,7 @@ extern void set_die_routine(void (*routine)(const char *err, va_list params) NOR extern int prefixcmp(const char *str, const char *prefix); extern void set_buildid_dir(void); +extern void disable_buildid_cache(void); static inline const char *skip_prefix(const char *str, const char *prefix) {