perf evsel: Introduce per cpu and per thread open helpers

Abstracting away the loops needed to create the various event fd handlers.

The users have to pass a confiruged perf->evsel.attr field, which is already
usable after perf_evsel__new (constructor) time, using defaults.

Comes out of the ad-hoc routines in builtin-stat, that now uses it.

Fixed a small silly bug where we were die()ing before killing our
children, dysfunctional family this one 8-)

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>

3 files changed, 83 insertions, 58 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a8b00b44b3cd..065e79eb2142 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -53,8 +53,6 @@
 #include <math.h>
 #include <locale.h>
 
-#define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
-
 #define DEFAULT_SEPARATOR       " "
 
 static struct perf_event_attr default_attrs[] = {
@@ -160,56 +158,24 @@ struct stats			runtime_cycles_stats[MAX_NR_CPUS];
 struct stats                    runtime_branches_stats[MAX_NR_CPUS];
 struct stats                    walltime_nsecs_stats;
 
-#define ERR_PERF_OPEN \
-"counter %d, sys_perf_event_open() syscall returned with %d (%s).  /bin/dmesg may provide additional information."
-
-static int create_perf_stat_counter(struct perf_evsel *evsel, bool *perm_err)
+static int create_perf_stat_counter(struct perf_evsel *evsel)
 {
         struct perf_event_attr *attr = &evsel->attr;
-        int thread;
-        int ncreated = 0;
 
         if (scale)
                 attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
                                     PERF_FORMAT_TOTAL_TIME_RUNNING;
 
-        if (system_wide) {
-                int cpu;
-
-                for (cpu = 0; cpu < nr_cpus; cpu++) {
-                        FD(evsel, cpu, 0) = sys_perf_event_open(attr,
-                                        -1, cpumap[cpu], -1, 0);
-                        if (FD(evsel, cpu, 0) < 0) {
-                                if (errno == EPERM || errno == EACCES)
-                                        *perm_err = true;
-                                error(ERR_PERF_OPEN, evsel->idx,
-                                        FD(evsel, cpu, 0), strerror(errno));
-                        } else {
-                                ++ncreated;
-                        }
-                }
-        } else {
-                attr->inherit = !no_inherit;
-                if (target_pid == -1 && target_tid == -1) {
-                        attr->disabled = 1;
-                        attr->enable_on_exec = 1;
-                }
-                for (thread = 0; thread < thread_num; thread++) {
-                        FD(evsel, 0, thread) = sys_perf_event_open(attr,
-                                all_tids[thread], -1, -1, 0);
-                        if (FD(evsel, 0, thread) < 0) {
-                                if (errno == EPERM || errno == EACCES)
-                                        *perm_err = true;
-                                error(ERR_PERF_OPEN, evsel->idx,
-                                        FD(evsel, 0, thread),
-                                         strerror(errno));
-                        } else {
-                                ++ncreated;
-                        }
-                }
+        if (system_wide)
+                return perf_evsel__open_per_cpu(evsel, nr_cpus, cpumap);
+
+        attr->inherit = !no_inherit;
+        if (target_pid == -1 && target_tid == -1) {
+                attr->disabled = 1;
+                attr->enable_on_exec = 1;
         }
 
-        return ncreated;
+        return perf_evsel__open_per_thread(evsel, thread_num, all_tids);
 }
 
 /*
@@ -289,9 +255,7 @@ static int run_perf_stat(int argc __used, const char **argv)
         unsigned long long t0, t1;
         struct perf_evsel *counter;
         int status = 0;
-        int ncreated = 0;
         int child_ready_pipe[2], go_pipe[2];
-        bool perm_err = false;
         const bool forks = (argc > 0);
         char buf;
 
@@ -349,19 +313,23 @@ static int run_perf_stat(int argc __used, const char **argv)
                 close(child_ready_pipe[0]);
         }
 
-        list_for_each_entry(counter, &evsel_list, node)
-                ncreated += create_perf_stat_counter(counter, &perm_err);
-
-        if (ncreated < nr_counters) {
-                if (perm_err)
-                        error("You may not have permission to collect %sstats.\n"
-                              "\t Consider tweaking"
-                              " /proc/sys/kernel/perf_event_paranoid or running as root.",
-                              system_wide ? "system-wide " : "");
-                die("Not all events could be opened.\n");
-                if (child_pid != -1)
-                        kill(child_pid, SIGTERM);
-                return -1;
+        list_for_each_entry(counter, &evsel_list, node) {
+                if (create_perf_stat_counter(counter) < 0) {
+                        if (errno == -EPERM || errno == -EACCES) {
+                                error("You may not have permission to collect %sstats.\n"
+                                      "\t Consider tweaking"
+                                      " /proc/sys/kernel/perf_event_paranoid or running as root.",
+                                      system_wide ? "system-wide " : "");
+                        } else {
+                                error("open_counter returned with %d (%s). "
+                                      "/bin/dmesg may provide additional information.\n",
+                                       errno, strerror(errno));
+                        }
+                        if (child_pid != -1)
+                                kill(child_pid, SIGTERM);
+                        die("Not all events could be opened.\n");
+                        return -1;
+                }
         }
 
         /*
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 3f5de5196231..e62cc5e050ab 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1,4 +1,5 @@
 #include "evsel.h"
+#include "../perf.h"
 #include "util.h"
 
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
@@ -121,3 +122,54 @@ int __perf_evsel__read(struct perf_evsel *evsel,
 
         return 0;
 }
+
+int perf_evsel__open_per_cpu(struct perf_evsel *evsel, int ncpus, int *cpu_map)
+{
+        int cpu;
+
+        for (cpu = 0; cpu < ncpus; cpu++) {
+                FD(evsel, cpu, 0) = sys_perf_event_open(&evsel->attr, -1,
+                                                        cpu_map[cpu], -1, 0);
+                if (FD(evsel, cpu, 0) < 0)
+                        goto out_close;
+        }
+
+        return 0;
+
+out_close:
+        while (--cpu >= 0) {
+                close(FD(evsel, cpu, 0));
+                FD(evsel, cpu, 0) = -1;
+        }
+        return -1;
+}
+
+int perf_evsel__open_per_thread(struct perf_evsel *evsel, int nthreads, int *thread_map)
+{
+        int thread;
+
+        for (thread = 0; thread < nthreads; thread++) {
+                FD(evsel, 0, thread) = sys_perf_event_open(&evsel->attr,
+                                                           thread_map[thread], -1, -1, 0);
+                if (FD(evsel, 0, thread) < 0)
+                        goto out_close;
+        }
+
+        return 0;
+
+out_close:
+        while (--thread >= 0) {
+                close(FD(evsel, 0, thread));
+                FD(evsel, 0, thread) = -1;
+        }
+        return -1;
+}
+
+int perf_evsel__open(struct perf_evsel *evsel, int ncpus, int nthreads,
+                     int *cpu_map, int *thread_map)
+{
+        if (nthreads < 0)
+                return perf_evsel__open_per_cpu(evsel, ncpus, cpu_map);
+
+        return perf_evsel__open_per_thread(evsel, nthreads, thread_map);
+}
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 8b48ef1e672c..a62fb55cffa7 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -42,6 +42,11 @@ int perf_evsel__alloc_counts(struct perf_evsel *evsel, int ncpus);
 void perf_evsel__free_fd(struct perf_evsel *evsel);
 void perf_evsel__close_fd(struct perf_evsel *evsel, int ncpus, int nthreads);
 
+int perf_evsel__open_per_cpu(struct perf_evsel *evsel, int ncpus, int *cpu_map);
+int perf_evsel__open_per_thread(struct perf_evsel *evsel, int nthreads, int *thread_map);
+int perf_evsel__open(struct perf_evsel *evsel, int ncpus, int nthreads,
+                     int *cpu_map, int *thread_map);
+
 #define perf_evsel__match(evsel, t, c)          \
         (evsel->attr.type == PERF_TYPE_##t &&   \
          evsel->attr.config == PERF_COUNT_##c)