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perf evsel: Fix use of inherit

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perf stat doesn't mmap and its perfectly fine for it to use task-bound
counters with inheritance.

So set the attr.inherit on the caller and leave the syscall itself to
validate it.

When the mmap fails perf_evlist__mmap will just emit a warning if this
is the failure reason.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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>
Link: http://lkml.kernel.org/r/20110414170121.GC3229@ghostprotocols.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo
2011-04-14 11:20:14 -03:00
parent db9a9cbc81
commit 5d2cd90922
8 changed files with 42 additions and 43 deletions
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27
tools/perf/util/evsel.c
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@@ -175,7 +175,7 @@ int __perf_evsel__read(struct perf_evsel *evsel,
}
static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
struct thread_map *threads, bool group, bool inherit)
struct thread_map *threads, bool group)
{
int cpu, thread;
unsigned long flags = 0;
@@ -192,19 +192,6 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
for (cpu = 0; cpu < cpus->nr; cpu++) {
int group_fd = -1;
/*
* Don't allow mmap() of inherited per-task counters. This
* would create a performance issue due to all children writing
* to the same buffer.
*
* FIXME:
* Proper fix is not to pass 'inherit' to perf_evsel__open*,
* but a 'flags' parameter, with 'group' folded there as well,
* then introduce a PERF_O_{MMAP,GROUP,INHERIT} enum, and if
* O_MMAP is set, emit a warning if cpu < 0 and O_INHERIT is
* set. Lets go for the minimal fix first tho.
*/
evsel->attr.inherit = (cpus->map[cpu] >= 0) && inherit;
for (thread = 0; thread < threads->nr; thread++) {
@@ -253,7 +240,7 @@ static struct {
};
int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
struct thread_map *threads, bool group, bool inherit)
struct thread_map *threads, bool group)
{
if (cpus == NULL) {
/* Work around old compiler warnings about strict aliasing */
@@ -263,19 +250,19 @@ int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
if (threads == NULL)
threads = &empty_thread_map.map;
return __perf_evsel__open(evsel, cpus, threads, group, inherit);
return __perf_evsel__open(evsel, cpus, threads, group);
}
int perf_evsel__open_per_cpu(struct perf_evsel *evsel,
struct cpu_map *cpus, bool group, bool inherit)
struct cpu_map *cpus, bool group)
{
return __perf_evsel__open(evsel, cpus, &empty_thread_map.map, group, inherit);
return __perf_evsel__open(evsel, cpus, &empty_thread_map.map, group);
}
int perf_evsel__open_per_thread(struct perf_evsel *evsel,
struct thread_map *threads, bool group, bool inherit)
struct thread_map *threads, bool group)
{
return __perf_evsel__open(evsel, &empty_cpu_map.map, threads, group, inherit);
return __perf_evsel__open(evsel, &empty_cpu_map.map, threads, group);
}
static int perf_event__parse_id_sample(const union perf_event *event, u64 type,