diff options
| author | Paul Mackerras <paulus@samba.org> | 2010-03-10 20:36:09 +1100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-03-11 13:36:53 +0100 |
| commit | a12b51c478899fe0b7e874a559b05ba35f1128ee (patch) | |
| tree | 25b9911c1932c13fd8b468aa18eb17982ba31b59 /tools/perf/builtin-record.c | |
| parent | 220b140b52ab6cc133f674a7ffec8fa792054f25 (diff) | |
perf tools: Fix sparse CPU numbering related bugs
At present, the perf subcommands that do system-wide monitoring
(perf stat, perf record and perf top) don't work properly unless
the online cpus are numbered 0, 1, ..., N-1. These tools ask
for the number of online cpus with sysconf(_SC_NPROCESSORS_ONLN)
and then try to create events for cpus 0, 1, ..., N-1.
This creates problems for systems where the online cpus are
numbered sparsely. For example, a POWER6 system in
single-threaded mode (i.e. only running 1 hardware thread per
core) will have only even-numbered cpus online.
This fixes the problem by reading the /sys/devices/system/cpu/online
file to find out which cpus are online. The code that does that is in
tools/perf/util/cpumap.[ch], and consists of a read_cpu_map()
function that sets up a cpumap[] array and returns the number of
online cpus. If /sys/devices/system/cpu/online can't be read or
can't be parsed successfully, it falls back to using sysconf to
ask how many cpus are online and sets up an identity map in cpumap[].
The perf record, perf stat and perf top code then calls
read_cpu_map() in the system-wide monitoring case (instead of
sysconf) and uses cpumap[] to get the cpu numbers to pass to
perf_event_open.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
LKML-Reference: <20100310093609.GA3959@brick.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'tools/perf/builtin-record.c')
| -rw-r--r-- | tools/perf/builtin-record.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index f573bbb83572..b09d3b27ca14 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -22,6 +22,7 @@ #include "util/debug.h" #include "util/session.h" #include "util/symbol.h" +#include "util/cpumap.h" #include <unistd.h> #include <sched.h> @@ -421,9 +422,6 @@ static int __cmd_record(int argc, const char **argv) char buf; page_size = sysconf(_SC_PAGE_SIZE); - nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); - assert(nr_cpus <= MAX_NR_CPUS); - assert(nr_cpus >= 0); atexit(sig_atexit); signal(SIGCHLD, sig_handler); @@ -547,8 +545,9 @@ static int __cmd_record(int argc, const char **argv) if ((!system_wide && !inherit) || profile_cpu != -1) { open_counters(profile_cpu, target_pid); } else { + nr_cpus = read_cpu_map(); for (i = 0; i < nr_cpus; i++) - open_counters(i, target_pid); + open_counters(cpumap[i], target_pid); } if (file_new) { |