Messages in this thread Patch in this message |  | | Date | Thu, 26 Mar 2020 23:36:51 -0700 | Subject | [PATCH] perf synthetic-events: save 4kb from 2 stack frames | From | Ian Rogers <> |
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Reduce the scope of PATH_MAX sized char buffers so that the compiler can overlap their usage.
perf_event__synthesize_mmap_events before 'sub $0x45b8,%rsp' after 'sub $0x35b8,%rsp'.
perf_event__get_comm_ids before 'sub $0x2028,%rsp' after 'sub $0x1028,%rsp'.
Signed-off-by: Ian Rogers <irogers@google.com> --- tools/perf/util/synthetic-events.c | 46 ++++++++++++++++++------------ 1 file changed, 27 insertions(+), 19 deletions(-)
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index 3f28af39f9c6..9ff54707bb30 100644 --- a/tools/perf/util/synthetic-events.c +++ b/tools/perf/util/synthetic-events.c @@ -70,7 +70,6 @@ int perf_tool__process_synth_event(struct perf_tool *tool, static int perf_event__get_comm_ids(pid_t pid, char *comm, size_t len, pid_t *tgid, pid_t *ppid) { - char filename[PATH_MAX]; char bf[4096]; int fd; size_t size = 0; @@ -80,12 +79,16 @@ static int perf_event__get_comm_ids(pid_t pid, char *comm, size_t len, *tgid = -1; *ppid = -1; - snprintf(filename, sizeof(filename), "/proc/%d/status", pid); + { + char filename[PATH_MAX]; - fd = open(filename, O_RDONLY); - if (fd < 0) { - pr_debug("couldn't open %s\n", filename); - return -1; + snprintf(filename, sizeof(filename), "/proc/%d/status", pid); + + fd = open(filename, O_RDONLY); + if (fd < 0) { + pr_debug("couldn't open %s\n", filename); + return -1; + } } n = read(fd, bf, sizeof(bf) - 1); @@ -280,7 +283,6 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, struct machine *machine, bool mmap_data) { - char filename[PATH_MAX]; FILE *fp; unsigned long long t; bool truncation = false; @@ -292,18 +294,22 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, if (machine__is_default_guest(machine)) return 0; - snprintf(filename, sizeof(filename), "%s/proc/%d/task/%d/maps", - machine->root_dir, pid, pid); +#define FILENAME_FMT_STRING "%s/proc/%d/task/%d/maps" + { + char filename[PATH_MAX]; - fp = fopen(filename, "r"); - if (fp == NULL) { - /* - * We raced with a task exiting - just return: - */ - pr_debug("couldn't open %s\n", filename); - return -1; - } + snprintf(filename, sizeof(filename), FILENAME_FMT_STRING, + machine->root_dir, pid, pid); + fp = fopen(filename, "r"); + if (fp == NULL) { + /* + * We raced with a task exiting - just return: + */ + pr_debug("couldn't open %s\n", filename); + return -1; + } + } event->header.type = PERF_RECORD_MMAP2; t = rdclock(); @@ -320,10 +326,10 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, break; if ((rdclock() - t) > timeout) { - pr_warning("Reading %s time out. " + pr_warning("Reading " FILENAME_FMT_STRING " time out. " "You may want to increase " "the time limit by --proc-map-timeout\n", - filename); + machine->root_dir, pid, pid); truncation = true; goto out; } @@ -412,6 +418,8 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, fclose(fp); return rc; + +#undef FILENAME_FMT_STRING } int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t process, -- 2.25.1.696.g5e7596f4ac-goog
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