summaryrefslogtreecommitdiffstats
path: root/tools/build
diff options
context:
space:
mode:
authorJan Stancek <jstancek@redhat.com>2017-02-17 12:10:26 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-02-17 12:56:35 -0300
commitda8a58b56c661681f9b2fd2fa59c6da3a5bac8d1 (patch)
tree6c3d7be2c88dd61e006831715244fccf951cf35f /tools/build
parent43db2843a4a41cc8cdb6ab696639aeee1f4d5062 (diff)
downloadlinux-da8a58b56c661681f9b2fd2fa59c6da3a5bac8d1.tar.bz2
perf tools: Replace _SC_NPROCESSORS_CONF with max_present_cpu in cpu_topology_map
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>
Diffstat (limited to 'tools/build')
0 files changed, 0 insertions, 0 deletions