[PATCH] [PATCH v2] perf: Modify MAX_NR_CPUS and MAX_CACHES
From: Kyle Meyer
Date: Fri Jun 28 2019 - 11:36:51 EST
Perf surpasses the limit of MAX_NR_CPUS and MAX_CACHES while attempting to
profile 1024 or more CPUs. Increase and/or make each limit dynamic to
regain normal functionality.
Before:
perf record -a
[ perf record: Woken up X times to write data ]
way too many cpu caches..
[ perf record: Captured and wrote X MB perf.data (X samples) ]
perf report -C 1024
Error: failed to set cpu bitmap
Requested CPU 1024 too large. Consider raising MAX_NR_CPUS
After:
perf record -a
[ perf record: Woken up X times to write data ]
[ perf record: Captured and wrote X MB perf.data (X samples) ]
perf report -C 1024
...
The variables nr_cpus_onln and max_caches are alternatives for MAX_NR_CPUS
and MAX_CACHES, they are initialized at runtime. MAX_NR_CPUS is increased
from 1024 to 2048 as it is still used by DECLARE_BITMAP() at compile time,
nr_cpus_onln replaces it elsewhere throughout perf.
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: Russ Anderson <russ.anderson@xxxxxxx>
Signed-off-by: Kyle Meyer <kyle.meyer@xxxxxxx>
---
tools/perf/perf.c | 6 ++++++
tools/perf/perf.h | 3 ++-
tools/perf/util/cpumap.c | 6 +++---
tools/perf/util/header.c | 7 +++----
tools/perf/util/machine.c | 11 +++++------
tools/perf/util/session.c | 5 ++---
tools/perf/util/stat.c | 4 ++--
tools/perf/util/svghelper.c | 10 +++++-----
8 files changed, 28 insertions(+), 24 deletions(-)
diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 72df4b6fa36f..c2c22476a65f 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -427,6 +427,12 @@ int main(int argc, const char **argv)
const char *cmd;
char sbuf[STRERR_BUFSIZE];
+ nr_cpus_onln = sysconf(_SC_NPROCESSORS_ONLN);
+ if (nr_cpus_onln < 0) {
+ fprintf(stderr, "Cannot determine the number of CPUs currently online.\n");
+ goto out;
+ }
+
/* libsubcmd init */
exec_cmd_init("perf", PREFIX, PERF_EXEC_PATH, EXEC_PATH_ENVIRONMENT);
pager_init(PERF_PAGER_ENVIRONMENT);
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 711e009381ec..603391cac85b 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -26,9 +26,10 @@ static inline unsigned long long rdclock(void)
}
#ifndef MAX_NR_CPUS
-#define MAX_NR_CPUS 1024
+#define MAX_NR_CPUS 2048
#endif
+int nr_cpus_onln;
extern const char *input_name;
extern bool perf_host, perf_guest;
extern const char perf_version_string[];
diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index c11a459ca582..83c05afef063 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -72,7 +72,7 @@ struct cpu_map *cpu_map__read(FILE *file)
int new_max = nr_cpus + cpu - prev - 1;
if (new_max >= max_entries) {
- max_entries = new_max + MAX_NR_CPUS / 2;
+ max_entries = new_max + nr_cpus_onln / 2;
tmp = realloc(tmp_cpus, max_entries * sizeof(int));
if (tmp == NULL)
goto out_free_tmp;
@@ -83,7 +83,7 @@ struct cpu_map *cpu_map__read(FILE *file)
tmp_cpus[nr_cpus++] = prev;
}
if (nr_cpus == max_entries) {
- max_entries += MAX_NR_CPUS;
+ max_entries += nr_cpus_onln;
tmp = realloc(tmp_cpus, max_entries * sizeof(int));
if (tmp == NULL)
goto out_free_tmp;
@@ -170,7 +170,7 @@ struct cpu_map *cpu_map__new(const char *cpu_list)
goto invalid;
if (nr_cpus == max_entries) {
- max_entries += MAX_NR_CPUS;
+ max_entries += nr_cpus_onln;
tmp = realloc(tmp_cpus, max_entries * sizeof(int));
if (tmp == NULL)
goto invalid;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 06ddb6618ef3..78f1acb069ed 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1121,16 +1121,15 @@ static int build_caches(struct cpu_cache_level caches[], u32 size, u32 *cntp)
return 0;
}
-#define MAX_CACHES 2000
-
static int write_cache(struct feat_fd *ff,
struct perf_evlist *evlist __maybe_unused)
{
- struct cpu_cache_level caches[MAX_CACHES];
+ u32 max_caches = (nr_cpus_onln * 4);
+ struct cpu_cache_level caches[max_caches];
u32 cnt = 0, i, version = 1;
int ret;
- ret = build_caches(caches, MAX_CACHES, &cnt);
+ ret = build_caches(caches, max_caches, &cnt);
if (ret)
goto out;
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 17eec39e775e..b4d792dbeb1f 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2593,7 +2593,7 @@ int __machine__synthesize_threads(struct machine *machine, struct perf_tool *too
pid_t machine__get_current_tid(struct machine *machine, int cpu)
{
- if (cpu < 0 || cpu >= MAX_NR_CPUS || !machine->current_tid)
+ if (cpu < 0 || cpu >= nr_cpus_onln || !machine->current_tid)
return -1;
return machine->current_tid[cpu];
@@ -2610,16 +2610,15 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
if (!machine->current_tid) {
int i;
- machine->current_tid = calloc(MAX_NR_CPUS, sizeof(pid_t));
+ machine->current_tid = calloc(nr_cpus_onln, sizeof(pid_t));
if (!machine->current_tid)
return -ENOMEM;
- for (i = 0; i < MAX_NR_CPUS; i++)
+ for (i = 0; i < nr_cpus_onln; i++)
machine->current_tid[i] = -1;
}
- if (cpu >= MAX_NR_CPUS) {
- pr_err("Requested CPU %d too large. ", cpu);
- pr_err("Consider raising MAX_NR_CPUS\n");
+ if (cpu >= nr_cpus_onln) {
+ pr_err("Requested CPU %d too large, there are %d CPUs currently online.\n", cpu, nr_cpus_onln);
return -EINVAL;
}
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 54cf163347f7..8641364555fb 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2289,9 +2289,8 @@ int perf_session__cpu_bitmap(struct perf_session *session,
for (i = 0; i < map->nr; i++) {
int cpu = map->map[i];
- if (cpu >= MAX_NR_CPUS) {
- pr_err("Requested CPU %d too large. "
- "Consider raising MAX_NR_CPUS\n", cpu);
+ if (cpu >= nr_cpus_onln) {
+ pr_err("Requested CPU %d too large, there are %d CPUs currently online.\n", cpu, nr_cpus_onln);
goto out_delete_map;
}
diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
index d91fe754b6d2..9d4a3b96496a 100644
--- a/tools/perf/util/stat.c
+++ b/tools/perf/util/stat.c
@@ -207,7 +207,7 @@ void perf_evlist__reset_stats(struct perf_evlist *evlist)
static void zero_per_pkg(struct perf_evsel *counter)
{
if (counter->per_pkg_mask)
- memset(counter->per_pkg_mask, 0, MAX_NR_CPUS);
+ memset(counter->per_pkg_mask, 0, nr_cpus_onln);
}
static int check_per_pkg(struct perf_evsel *counter,
@@ -226,7 +226,7 @@ static int check_per_pkg(struct perf_evsel *counter,
return 0;
if (!mask) {
- mask = zalloc(MAX_NR_CPUS);
+ mask = zalloc(nr_cpus_onln);
if (!mask)
return -ENOMEM;
diff --git a/tools/perf/util/svghelper.c b/tools/perf/util/svghelper.c
index fab8a048d31b..6a8241932dce 100644
--- a/tools/perf/util/svghelper.c
+++ b/tools/perf/util/svghelper.c
@@ -705,7 +705,7 @@ static void scan_thread_topology(int *map, struct topology *t, int cpu, int *pos
for_each_set_bit(thr,
cpumask_bits(&t->sib_thr[i]),
- MAX_NR_CPUS)
+ nr_cpus_onln)
if (map[thr] == -1)
map[thr] = (*pos)++;
}
@@ -720,7 +720,7 @@ static void scan_core_topology(int *map, struct topology *t)
for (i = 0; i < t->sib_core_nr; i++)
for_each_set_bit(cpu,
cpumask_bits(&t->sib_core[i]),
- MAX_NR_CPUS)
+ nr_cpus_onln)
scan_thread_topology(map, t, cpu, &pos);
}
@@ -737,7 +737,7 @@ static int str_to_bitmap(char *s, cpumask_t *b)
for (i = 0; i < m->nr; i++) {
c = m->map[i];
- if (c >= MAX_NR_CPUS) {
+ if (c >= nr_cpus_onln) {
ret = -1;
break;
}
@@ -784,13 +784,13 @@ int svg_build_topology_map(char *sib_core, int sib_core_nr,
sib_thr += strlen(sib_thr) + 1;
}
- topology_map = malloc(sizeof(int) * MAX_NR_CPUS);
+ topology_map = malloc(sizeof(int) * nr_cpus_onln);
if (!topology_map) {
fprintf(stderr, "topology: no memory\n");
goto exit;
}
- for (i = 0; i < MAX_NR_CPUS; i++)
+ for (i = 0; i < nr_cpus_onln; i++)
topology_map[i] = -1;
scan_core_topology(topology_map, &t);
--
2.12.3