Messages in this thread | | | Date | Wed, 17 Jul 2019 09:30:06 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH] [PATCH v2] perf: Modify MAX_NR_CPUS and MAX_CACHES |
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On Fri, Jun 28, 2019 at 10:35:55AM -0500, Kyle Meyer wrote: > 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.
I overlooked this one and it no longer applies because of another change from you: 9f94c7f947e9 perf tools: Increase MAX_NR_CPUS and MAX_CACHES
my worry here (did not check completely) is that some paths you changed can't use number of cpus from sysconf(_SC_NPROCESSORS_ONLN), because they are within the report code path, and the data can come from another machine with different number of cpus
jirka
> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Arnaldo Carvalho de Melo <acme@kernel.org> > Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> > Cc: Jiri Olsa <jolsa@redhat.com> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: linux-kernel@vger.kernel.org > Cc: Russ Anderson <russ.anderson@hpe.com> > Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com> > --- > 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 >
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