Re: [PATCH] perf tools: Replace MAX_NR_CPUS with nr_cpus_onln

[Jiri Olsa <jolsa@redhat.com>]

On Fri, Jul 26, 2019 at 02:51:39PM -0500, Kyle Meyer wrote:
> The variables nr_cpus_onln and max_caches are dynamic alternatives for
> MAX_NR_CPUS and MAX_CACHES as they are initialized at runtime. MAX_NR_CPUS
> is still used by DECLARE_BITMAP() at compile time, however, nr_cpus_onln
> replaces it elsewhere throughout perf.
> 
> This patch was tested using "perf record -a -g" on both an eight socket
> (288 CPUs) system and a single socket (36 CPUs) system. Each system was then
> rebooted single socket (36 CPUs) / eight socket (288 CPUs) and "perf
> report" used to read the perf.data file. "perf report --header" was used to
> confirm that each perf.data had information on 288 CPUs / 36 CPUs.
> 
> This patch is meant to be built against perf tools: Increase MAX_NR_CPUS and
> MAX_CACHES (commit 9f94c7f947e919c343b30f080285af53d0fa9902).

hi,
could you please rebase to latest Arnaldo's perf/core,
the cpumap.c got changed recently and I can't apply
your patch anymore:

	patching file perf.c
	patching file perf.h
	patching file util/cpumap.c
	Hunk #1 FAILED at 72.
	Hunk #2 FAILED at 83.
	Hunk #3 FAILED at 170.
	3 out of 3 hunks FAILED -- saving rejects to file util/cpumap.c.rej
	patching file util/header.c
	Hunk #1 succeeded at 1126 with fuzz 2 (offset 1 line).
	patching file util/machine.c
	patching file util/stat.c
	Hunk #1 succeeded at 208 with fuzz 1.
	patching file util/svghelper.c
	Hunk #1 succeeded at 706 (offset 1 line).
	Hunk #2 succeeded at 721 (offset 1 line).
	Hunk #3 succeeded at 738 (offset 1 line).
	Hunk #4 succeeded at 785 (offset 1 line).

thanks,
jirka

> 
> Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com>
> Cc: Russ Anderson <russ.anderson@hpe.com>
> 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
> ---
>  tools/perf/perf.c           | 10 ++++++++++
>  tools/perf/perf.h           |  1 +
>  tools/perf/util/cpumap.c    |  6 +++---
>  tools/perf/util/header.c    |  5 +++--
>  tools/perf/util/machine.c   | 11 +++++------
>  tools/perf/util/stat.c      |  4 ++--
>  tools/perf/util/svghelper.c | 10 +++++-----
>  7 files changed, 29 insertions(+), 18 deletions(-)
> 
> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> index 97e2628ea5dd..0d0162fb4e24 100644
> --- a/tools/perf/perf.c
> +++ b/tools/perf/perf.c
> @@ -428,6 +428,16 @@ 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;
> +	} 
> +	if (nr_cpus_onln > MAX_NR_CPUS) {
> +		fprintf(stderr, "The number of CPUs currently online is too large, consider raising MAX_NR_CPUS.\n");
> +		nr_cpus_onln = MAX_NR_CPUS;
> +	}
> +
>  	/* 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 74d0124d38f3..603391cac85b 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -29,6 +29,7 @@ static inline unsigned long long rdclock(void)
>  #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 3acfbe34ebaf..f634c56b1388 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 c24db7f4909c..030c0a8f6664 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1125,11 +1125,12 @@ static int build_caches(struct cpu_cache_level caches[], u32 size, u32 *cntp)
>  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 cf826eca3aaf..92720240676d 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -2615,7 +2615,7 @@ 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];
> @@ -2632,16 +2632,15 @@ 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/stat.c b/tools/perf/util/stat.c
> index db8a6cf336be..f87bdc140a4b 100644
> --- a/tools/perf/util/stat.c
> +++ b/tools/perf/util/stat.c
> @@ -208,7 +208,7 @@ 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,
> @@ -227,7 +227,7 @@ 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 76cc54000483..4c38f70520c5 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
>