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SubjectRe: [PATCH 04/13] perf env: Introduce read_cpu_topology_map() method


On 2015/9/10 21:12, Arnaldo Carvalho de Melo wrote:

[SNIP]

> +
> +int perf_env__read_cpu_topology_map(struct perf_env *env)
> +{
> + int cpu, nr_cpus;
> +
> + if (env->cpu != NULL)
> + return 0;
> +
> + if (env->nr_cpus_avail == 0)
> + env->nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
> +
> + nr_cpus = env->nr_cpus_avail;
> + if (nr_cpus == -1)
> + return -EINVAL;
> +
> + env->cpu = calloc(nr_cpus, sizeof(env->cpu[0]));
> + if (env->cpu == NULL)
> + return -ENOMEM;
> +
> + for (cpu = 0; cpu < nr_cpus; ++cpu) {
> + env->cpu[cpu].core_id = cpu_map__get_core_id(cpu);
> + env->cpu[cpu].socket_id = cpu_map__get_socket_id(cpu);
> + }

Shouldn't we check the failure of these two functions?

At this point perf_env__read_cpu_topology_map and build_cpu_topology are
doing
similar things. build_cpu_topology() reads
/sys/xxxxx/cpu%d/topology/{core,thread}_siblings_list,
perf_env__read_cpu_topology_map() reads /sys/xxxxx/cpu%d/topology/core_id,
but build_cpu_topology() returns error if any read failed, but
perf_env__read_cpu_topology_map() fills core_id and socket_id with -1 if
read fail.

I tried to offline a core between build_cpu_topology() and
perf_env__read_cpu_topology_map(),
and perf report say:

# perf report -v --header-only -I
build id event received for [kernel.kallsyms]: (...)
core_id number is too big.You may need to upgrade the perf tool. <--
*see this warning*
# ========
# captured on: Sun Feb 15 15:01:05 2009
# hostname : localhost
...
# sibling cores : ...
# sibling threads : 7
# Core ID and Socket ID information is not available
# pmu mappings: not available
# ========

Thank you.

> +
> + env->nr_cpus_avail = nr_cpus;
> + return 0;
> +}
> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> index 70124d9a1624..c4e36323d91e 100644
> --- a/tools/perf/util/env.h
> +++ b/tools/perf/util/env.h
> @@ -38,4 +38,6 @@ void perf_env__exit(struct perf_env *env);
>
> int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[]);
>
> +int perf_env__read_cpu_topology_map(struct perf_env *env);
> +
> #endif /* __PERF_ENV_H */
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 151b8310ac70..d6437465f70f 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -415,8 +415,6 @@ struct cpu_topo {
> u32 thread_sib;
> char **core_siblings;
> char **thread_siblings;
> - int *core_id;
> - int *phy_pkg_id;
> };
>
> static int build_cpu_topo(struct cpu_topo *tp, int cpu)
> @@ -479,9 +477,6 @@ try_threads:
> }
> ret = 0;
> done:
> - tp->core_id[cpu] = cpu_map__get_core_id(cpu);
> - tp->phy_pkg_id[cpu] = cpu_map__get_socket_id(cpu);
> -
> if(fp)
> fclose(fp);
> free(buf);
> @@ -509,7 +504,7 @@ static struct cpu_topo *build_cpu_topology(void)
> struct cpu_topo *tp;
> void *addr;
> u32 nr, i;
> - size_t sz, sz_id;
> + size_t sz;
> long ncpus;
> int ret = -1;
>
> @@ -520,9 +515,8 @@ static struct cpu_topo *build_cpu_topology(void)
> nr = (u32)(ncpus & UINT_MAX);
>
> sz = nr * sizeof(char *);
> - sz_id = nr * sizeof(int);
>
> - addr = calloc(1, sizeof(*tp) + 2 * sz + 2 * sz_id);
> + addr = calloc(1, sizeof(*tp) + 2 * sz);
> if (!addr)
> return NULL;
>
> @@ -532,10 +526,6 @@ static struct cpu_topo *build_cpu_topology(void)
> tp->core_siblings = addr;
> addr += sz;
> tp->thread_siblings = addr;
> - addr += sz;
> - tp->core_id = addr;
> - addr += sz_id;
> - tp->phy_pkg_id = addr;
>
> for (i = 0; i < nr; i++) {
> ret = build_cpu_topo(tp, i);
> @@ -554,7 +544,7 @@ static int write_cpu_topology(int fd, struct perf_header *h __maybe_unused,
> {
> struct cpu_topo *tp;
> u32 i;
> - int ret;
> + int ret, j;
>
> tp = build_cpu_topology();
> if (!tp)
> @@ -579,11 +569,17 @@ static int write_cpu_topology(int fd, struct perf_header *h __maybe_unused,
> break;
> }
>
> - for (i = 0; i < tp->cpu_nr; i++) {
> - ret = do_write(fd, &tp->core_id[i], sizeof(int));
> + ret = perf_env__read_cpu_topology_map(&perf_env);
> + if (ret < 0)
> + goto done;
> +
> + for (j = 0; j < perf_env.nr_cpus_avail; j++) {
> + ret = do_write(fd, &perf_env.cpu[j].core_id,
> + sizeof(perf_env.cpu[j].core_id));
> if (ret < 0)
> return ret;
> - ret = do_write(fd, &tp->phy_pkg_id[i], sizeof(int));
> + ret = do_write(fd, &perf_env.cpu[j].socket_id,
> + sizeof(perf_env.cpu[j].socket_id));
> if (ret < 0)
> return ret;
> }




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