Commit Graph

27 Commits

Author SHA1 Message Date
Mark Rutland
9a6c582d57 perf cpu_map: Add more helpers
In some cases it's necessry to figure out the map-local index of a given
Linux logical CPU ID. Add a new helper, cpu_map__idx, to acquire this.
As the logic is largely the same as the existing cpu_map__has, this is
rewritten in terms of the new helper.

At the same time, add the inverse operation, cpu_map__cpu, which yields
the logical CPU id for a map-local index. While this can be performed
manually, wrapping this in a helper can make code more legible.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1468577293-19667-3-git-send-email-mark.rutland@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-18 19:42:47 -03:00
Jiri Olsa
a24020e6b7 perf tools: Change cpu_map__fprintf output
Display cpu map in standard list form.  (perf report -D output on perf stat data).

before:
  0x590 [0x18]: PERF_RECORD_CPU_MAP nr: 4 cpus: 0, 1, 2, 3

after:
  0x590 [0x18]: PERF_RECORD_CPU_MAP: 0-3

Adding automated testcase.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1467113345-12669-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-06-30 18:27:45 -03:00
Jiri Olsa
e632aa69c9 perf cpu_map: Add has() method
Adding cpu_map__has() to return bool of cpu presence in cpus map.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1460467771-26532-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-04-13 10:11:50 -03:00
Arnaldo Carvalho de Melo
5ac76283b3 perf cpumap: Auto initialize cpu__max_{node,cpu}
Since it was always checking if the initialization was done, use that
branch to do the initialization if not done already.

With this we reduce the number of exported globals from these files.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20160125212955.GG22501@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-01-26 16:08:36 -03:00
Jiri Olsa
15d2b9956b perf cpumap: Fix cpu conversion in cpu_map__from_entries
We can't convert u16 cpu_map_entries::cpu[x] value directly to int,
because it could hold -1, which would be converted as 65535.

Adding special treatment for -1, which is not real cpu number, to be
converted to (int -1).

Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1452077397-31958-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-01-06 20:11:16 -03:00
Jiri Olsa
f77b57ad4f perf cpu_map: Add cpu_map__new_event function
Introducing the cpu_map__new_event function to create a struct cpu_map
object from a cpu_map event.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1445784728-21732-10-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-12-17 14:38:18 -03:00
Jiri Olsa
2322f573f8 perf cpu_map: Add cpu_map__empty_new function
Adding cpu_map__empty_new interface to create empty cpumap with given
size. The cpumap entries are initialized with -1.

It'll be used for caching cpu_map in following patches.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1445784728-21732-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-10-27 15:05:36 -03:00
Kan Liang
bc1d03687b perf cpu_map: Fix core dump caused by per-socket/core system-wide stat
Perf will core dump if --per-socket/core -a are applied for perf stat.

The root cause is that cpu_map__build_map set refcnt of evlist's cpu_map
to 1.  It should set refcnt for the newly created cpu_map, not evlist's
cpu_map.

Here is the example:

  # perf stat -e cycles --per-socket -a sleep 1

   Performance counter stats for 'system wide':

  S0       36         30,196,257      cycles
  S1       28         15,823,536      cycles

       1.001126828 seconds time elapsed

  *** Error in `./perf': corrupted double-linked list: 0x00000000021f9090 ***
  ======= Backtrace: =========
  /lib64/libc.so.6[0x3002e7bbe7]
  /lib64/libc.so.6[0x3002e7d2b5]
  ./perf(perf_evsel__delete+0x28)[0x485bdd]
  ./perf[0x4800e8]
  ./perf(perf_evlist__delete+0x5e)[0x482cd5]
  ./perf(cmd_stat+0xf25)[0x432328]
  ./perf[0x4768e0]
  ./perf[0x476ad6]
  ./perf[0x476b41]
  ./perf(main+0x1d0)[0x476db2]
  /lib64/libc.so.6(__libc_start_main+0xf5)[0x3002e21b45]
  ./perf[0x4202c5]

Signed-off-by: Kan Liang <kan.liang@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1444388363-35936-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-10-20 15:54:20 -03:00
Jiri Olsa
1fe7a30028 perf cpu_map: Add data arg to cpu_map__build_map callback
Adding data arg to cpu_map__build_map callback, so we could pass data
along to the callback. It'll be needed in following patches to retrieve
topology info from perf.data.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1444992092-17897-41-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-10-19 18:04:01 -03:00
Jiri Olsa
f1cbb8f357 perf cpu_map: Make cpu_map__build_map global
We'll need to call it from perf stat in the stat_script patchkit

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1444992092-17897-40-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-10-19 18:03:03 -03:00
Arnaldo Carvalho de Melo
5d8cf721cb perf cpu_map: Use sysfs__read_int in get_{core,socket}_id()
We have the tools/lib/ sysfs__read_int() for that, avoid code
duplication.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-fqg6vt5ku72pbf54ljg6tmoy@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-09-14 12:50:27 -03:00
Kan Liang
193b6bd339 perf cpumap: Factor out functions to get core_id and socket_id
This patch moves the code which reads core_id and socket_id into
separate functions.

Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1441115893-22006-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-09-02 16:30:47 -03:00
Jiri Olsa
f30a79b012 perf tools: Add reference counting for cpu_map object
Adding refference counting for cpu_map object, so it could be easily
shared among other objects.

Using cpu_map__put instead cpu_map__delete and making cpu_map__delete
static.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1435012588-9007-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-06-25 15:15:50 -03:00
Don Zickus
f5b1f4e483 perf tools: Use cpu/possible instead of cpu/kernel_max
The system's max configuration is represented by cpu/possible and
cpu/kernel_max can be huge (4096 vs. 128), so save space by keeping
smaller structures.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1396896924-129847-3-git-send-email-dzickus@redhat.com
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
2014-04-22 17:39:16 +02:00
Don Zickus
7780c25bae perf tools: Allow ability to map cpus to nodes easily
This patch figures out the max number of cpus and nodes that are on the
system and creates a map of cpu to node.  This allows us to provide a cpu
and quickly get the node associated with it.

It was mostly copied from builtin-kmem.c and tweaked slightly to use less memory
(use possible cpus instead of max).  It also calculates the max number of nodes.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1396896924-129847-2-git-send-email-dzickus@redhat.com
[ Removing out label code in init_cpunode_map ]
[ Adding check for snprintf error ]
[ Removing unneeded returns ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
2014-04-22 17:39:12 +02:00
Borislav Petkov
cd0cfad74e perf tools: Move fs.* to lib/api/fs/
Move to generic library and kill magic.h as it is needed only in fs.h.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stanislav Fomichev <stfomichev@yandex-team.ru>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1386605664-24041-3-git-send-email-bp@alien8.de
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-02-18 09:34:49 -03:00
Arnaldo Carvalho de Melo
cf38fadade perf fs: Rename NAME_find_mountpoint() to NAME__mountpoint()
Shorten it, "finding" it is an implementation detail, what callers want
is the pathname, not to ask for it to _always_ do the lookup.

And the existing implementation already caches it, i.e. it doesn't
"finds" it on every call.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-r24wa4bvtccg7mnkessrbbdj@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-11-05 15:15:00 -03:00
Jiri Olsa
4299a54997 perf tools: Factor sysfs code into generic fs object
Moving sysfs code into generic fs object and preparing it to carry
procfs support.

This should be merged with tools/lib/lk/debugfs.c at some point in the
future.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1383660887-1734-2-git-send-email-jolsa@redhat.com
[ Added fs__ namespace qualifier to some more functions ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-11-05 14:44:26 -03:00
Stephane Eranian
12c08a9f59 perf stat: Add per-core aggregation
This patch adds the --per-core option to perf stat.

This option is used to aggregate system-wide counts
on a per physical core basis. On processors with
hyperthreading, this means counts of all HT threads
running on a physical core are aggregated.

This mode is useful to find imblance between physical
cores running an uniform workload. Cores are identified
by socket: S0-C1, means physical core 1 on socket 0. Note
that cores are identified using their physical core id,
thus their numbering may not be continuous.

Per core aggregation can be combined with interval printing:

 # perf stat -a --per-core -I 1000 -e cycles sleep 1000
 #           time core         cpus             counts events
      1.000090030 S0-C0           1          4,765,747 cycles
      1.000090030 S0-C1           1          5,580,647 cycles
      1.000090030 S0-C2           1            221,181 cycles
      1.000090030 S0-C3           1            266,092 cycles

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1360846649-6411-4-git-send-email-eranian@google.com
[ committer note: Remove parts already applied on 86ee6e1 to keep bisectability ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-03-25 16:13:26 -03:00
Stephane Eranian
86ee6e18f6 perf stat: Refactor aggregation code
Refactor aggregation code by introducing a single aggr_mode variable and an
enum for aggregation.

Also refactor cpumap code having to do with cpu to socket mappings. All in
preparation for extended modes, such as cpu -> core.

Also fix socket aggregation and ensure that sockets are printed in increasing
order.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1360846649-6411-2-git-send-email-eranian@google.com
[ committer note: Fixup conflicts with a7e191c "--repeat forever" and
  acf2892 "Use perf_evlist__prepare/start_workload()" ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-03-25 15:29:53 -03:00
Stephane Eranian
5ac59a8a77 perf tools: Add cpu_map processor socket level functions
This patch adds:
- cpu_map__get_socket: get socked id from cpu
- cpu_map__build_socket_map: build socket map
- cpu_map__socket: gets acutal socket from logical socket

Those functions are used by uncore and processor socket-level
aggregation modes.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1360161962-9675-2-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-02-06 18:09:26 -03:00
Yan, Zheng
7ae92e744e perf stat: Check PMU cpumask file
If user doesn't explicitly specify CPU list, perf-stat only collects
events on CPUs listed in the PMU cpumask file.

Signed-off-by: "Yah, Zheng" <zheng.z.yan@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1347263631-23175-3-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-09-17 13:12:02 -03:00
Arnaldo Carvalho de Melo
9ae7d3351a perf tools: Add fprintf methods for thread_map and cpu_map classes
For helping with debugging.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-m06n4rp7pwr6dlzwoq89cl69@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-01-24 19:46:48 -02:00
Arnaldo Carvalho de Melo
915fce20ec perf tools: Add missing cpu_map__delete()
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2011-01-22 19:56:30 -02:00
Arnaldo Carvalho de Melo
60d567e2d9 perf tools: Refactor cpumap to hold nr and the map
So that later, we can pass the cpu_map instance instead of (nr_cpus, cpu_map)
for things like perf_evsel__open and friends.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2011-01-04 00:23:55 -02:00
Stephane Eranian
c45c6ea2e5 perf tools: Add the ability to specify list of cpus to monitor
This patch adds a -C option to stat, record, top to designate a list of CPUs to
monitor. CPUs can be specified as a comma-separated list or ranges, no space
allowed.

Examples:
$ perf record -a -C0-1,4-7 sleep 1
$ perf top -C0-4
$ perf stat -a -C1,2,3,4 sleep 1

With perf record in per-thread mode with inherit mode on, samples are collected
only when the thread runs on the designated CPUs.

The -C option does not turn on system-wide mode automatically.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4bff9496.d345d80a.41fe.7b00@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-06-05 09:33:01 -03:00
Paul Mackerras
a12b51c478 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>
2010-03-11 13:36:53 +01:00