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author | Ian Rogers <irogers@google.com> | 2020-04-02 17:43:55 +0200 |
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committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-04-16 17:19:13 +0200 |
commit | 04ed4ccb9c07868bc0cb41f699391332bf62220c (patch) | |
tree | 6abe33944f4ab3808d2182e2ac2a1d674644d724 /tools/perf/util/synthetic-events.c | |
parent | tools api fs: Make xxx__mountpoint() more scalable (diff) | |
download | linux-04ed4ccb9c07868bc0cb41f699391332bf62220c.tar.xz linux-04ed4ccb9c07868bc0cb41f699391332bf62220c.zip |
perf synthetic-events: save 4kb from 2 stack frames
Reuse an existing char buffer to avoid two PATH_MAX sized char buffers.
Reduces stack frame sizes by 4kb.
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'.
The performance impact of this change is negligible.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrey Zhizhikin <andrey.z@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/lkml/20200402154357.107873-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/synthetic-events.c')
-rw-r--r-- | tools/perf/util/synthetic-events.c | 22 |
1 files changed, 10 insertions, 12 deletions
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index a661b122d9d8..9d4aa951eaa6 100644 --- a/tools/perf/util/synthetic-events.c +++ b/tools/perf/util/synthetic-events.c @@ -71,7 +71,6 @@ 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; @@ -81,11 +80,11 @@ 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); + snprintf(bf, sizeof(bf), "/proc/%d/status", pid); - fd = open(filename, O_RDONLY); + fd = open(bf, O_RDONLY); if (fd < 0) { - pr_debug("couldn't open %s\n", filename); + pr_debug("couldn't open %s\n", bf); return -1; } @@ -281,9 +280,9 @@ 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; + char bf[BUFSIZ]; bool truncation = false; unsigned long long timeout = proc_map_timeout * 1000000ULL; int rc = 0; @@ -293,15 +292,15 @@ 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); + snprintf(bf, sizeof(bf), "%s/proc/%d/task/%d/maps", + machine->root_dir, pid, pid); - fp = fopen(filename, "r"); + fp = fopen(bf, "r"); if (fp == NULL) { /* * We raced with a task exiting - just return: */ - pr_debug("couldn't open %s\n", filename); + pr_debug("couldn't open %s\n", bf); return -1; } @@ -309,7 +308,6 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, t = rdclock(); while (1) { - char bf[BUFSIZ]; char prot[5]; char execname[PATH_MAX]; char anonstr[] = "//anon"; @@ -321,10 +319,10 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, break; if ((rdclock() - t) > timeout) { - pr_warning("Reading %s time out. " + pr_warning("Reading %s/proc/%d/task/%d/maps 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; } |