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perf tools: Replace _SC_NPROCESSORS_CONF with max_present_cpu in cpu_topology_map

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There are 2 problems wrt. cpu_topology_map on systems with sparse CPUs:

1. offline/absent CPUs will have their socket_id and core_id set to -1
   which triggers:
   "socket_id number is too big.You may need to upgrade the perf tool."

2. size of cpu_topology_map (perf_env.cpu[]) is allocated based on
   _SC_NPROCESSORS_CONF, but can be indexed with CPU ids going above.
   Users of perf_env.cpu[] are using CPU id as index. This can lead
   to read beyond what was allocated:
   ==19991== Invalid read of size 4
   ==19991==    at 0x490CEB: check_cpu_topology (topology.c:69)
   ==19991==    by 0x490CEB: test_session_topology (topology.c:106)
   ...

For example:
  _SC_NPROCESSORS_CONF == 16
  available: 2 nodes (0-1)
  node 0 cpus: 0 6 8 10 16 22 24 26
  node 0 size: 12004 MB
  node 0 free: 9470 MB
  node 1 cpus: 1 7 9 11 23 25 27
  node 1 size: 12093 MB
  node 1 free: 9406 MB
  node distances:
  node   0   1
    0:  10  20
    1:  20  10

This patch changes HEADER_NRCPUS.nr_cpus_available from _SC_NPROCESSORS_CONF
to max_present_cpu and updates any user of cpu_topology_map to iterate
with nr_cpus_avail.

As a consequence HEADER_CPU_TOPOLOGY core_id and socket_id lists get longer,
but maintain compatibility with pre-patch state - index to cpu_topology_map is
CPU id.

  perf test 36 -v
  36: Session topology                           :
  --- start ---
  test child forked, pid 22211
  templ file: /tmp/perf-test-gmdX5i
  CPU 0, core 0, socket 0
  CPU 1, core 0, socket 1
  CPU 6, core 10, socket 0
  CPU 7, core 10, socket 1
  CPU 8, core 1, socket 0
  CPU 9, core 1, socket 1
  CPU 10, core 9, socket 0
  CPU 11, core 9, socket 1
  CPU 16, core 0, socket 0
  CPU 22, core 10, socket 0
  CPU 23, core 10, socket 1
  CPU 24, core 1, socket 0
  CPU 25, core 1, socket 1
  CPU 26, core 9, socket 0
  CPU 27, core 9, socket 1
  test child finished with 0
  ---- end ----
  Session topology: Ok

Signed-off-by: Jan Stancek <jstancek@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/d7c05c6445fca74a8442c2c73cfffd349c52c44f.1487146877.git.jstancek@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jan Stancek 2017-02-17 12:10:26 +01:00 committed by Arnaldo Carvalho de Melo
parent 43db2843a4
commit da8a58b56c
4 changed files with 10 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
tools/perf/builtin-stat.c
View File

@ -1765,7 +1765,7 @@ static inline int perf_env__get_cpu(struct perf_env *env, struct cpu_map *map, i
cpu = map->map[idx];
if (cpu >= env->nr_cpus_online)
if (cpu >= env->nr_cpus_avail)
return -1;
return cpu;

4
tools/perf/tests/topology.c
View File

@ -65,7 +65,9 @@ static int check_cpu_topology(char *path, struct cpu_map *map)
session = perf_session__new(&file, false, NULL);
TEST_ASSERT_VAL("can't get session", session);
for (i = 0; i < session->header.env.nr_cpus_online; i++) {
for (i = 0; i < session->header.env.nr_cpus_avail; i++) {
if (!cpu_map__has(map, i))
continue;
pr_debug("CPU %d, core %d, socket %d\n", i,
session->header.env.cpu[i].core_id,
session->header.env.cpu[i].socket_id);

2
tools/perf/util/env.c
View File

@ -66,7 +66,7 @@ int perf_env__read_cpu_topology_map(struct perf_env *env)
return 0;
if (env->nr_cpus_avail == 0)
env->nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
env->nr_cpus_avail = cpu__max_present_cpu();
nr_cpus = env->nr_cpus_avail;
if (nr_cpus == -1)

16
tools/perf/util/header.c
View File

@ -295,11 +295,7 @@ static int write_nrcpus(int fd, struct perf_header *h __maybe_unused,
u32 nrc, nra;
int ret;
nr = sysconf(_SC_NPROCESSORS_CONF);
if (nr < 0)
return -1;
nrc = (u32)(nr & UINT_MAX);
nrc = cpu__max_present_cpu();
nr = sysconf(_SC_NPROCESSORS_ONLN);
if (nr < 0)
@ -513,9 +509,7 @@ static struct cpu_topo *build_cpu_topology(void)
int ret = -1;
struct cpu_map *map;
ncpus = sysconf(_SC_NPROCESSORS_CONF);
if (ncpus < 0)
return NULL;
ncpus = cpu__max_present_cpu();
/* build online CPU map */
map = cpu_map__new(NULL);
@ -1139,7 +1133,7 @@ static void print_cpu_topology(struct perf_header *ph, int fd __maybe_unused,
{
int nr, i;
char *str;
int cpu_nr = ph->env.nr_cpus_online;
int cpu_nr = ph->env.nr_cpus_avail;
nr = ph->env.nr_sibling_cores;
str = ph->env.sibling_cores;
@ -1794,7 +1788,7 @@ static int process_cpu_topology(struct perf_file_section *section,
u32 nr, i;
char *str;
struct strbuf sb;
int cpu_nr = ph->env.nr_cpus_online;
int cpu_nr = ph->env.nr_cpus_avail;
u64 size = 0;
ph->env.cpu = calloc(cpu_nr, sizeof(*ph->env.cpu));
@ -1875,7 +1869,7 @@ static int process_cpu_topology(struct perf_file_section *section,
if (ph->needs_swap)
nr = bswap_32(nr);
if (nr > (u32)cpu_nr) {
if (nr != (u32)-1 && nr > (u32)cpu_nr) {
pr_debug("socket_id number is too big."
"You may need to upgrade the perf tool.\n");
goto free_cpu;