The following commit has been merged into the perf/core branch of tip: Commit-ID: 04ed4ccb9c07868bc0cb41f699391332bf62220c Gitweb: https://git.kernel.org/tip/04ed4ccb9c07868bc0cb41f699391332bf62220c Author: Ian Rogers <irogers@xxxxxxxxxx> AuthorDate: Thu, 02 Apr 2020 08:43:55 -07:00 Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> CommitterDate: Thu, 16 Apr 2020 12:19:13 -03:00 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@xxxxxxxxxx> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> Cc: Andrey Zhizhikin <andrey.z@xxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx> Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Petr Mladek <pmladek@xxxxxxxx> Cc: Stephane Eranian <eranian@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lore.kernel.org/lkml/20200402154357.107873-4-irogers@xxxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> --- tools/perf/util/synthetic-events.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index a661b12..9d4aa95 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; }
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