[tip:perfcounters/core] perf stat: Continue even on counter creation error

tip-bot for Ingo Molnar
2009-06-07T15:13:23Z

Commit-ID: 743ee1f80434138495bbb95ffb897acf46b51d54
Gitweb: http://git.kernel.org/tip/743ee1f80434138495bbb95ffb897acf46b51d54
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Sun, 7 Jun 2009 17:06:46 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 7 Jun 2009 17:08:59 +0200

perf stat: Continue even on counter creation error

Before:

$ perf stat ~/hackbench 5

error: syscall returned with -1 (No such device)

After:

$ perf stat ~/hackbench 5
Time: 1.640

Performance counter stats for '/home/mingo/hackbench 5':

6524.570382 task-clock-ticks # 3.838 CPU utilization factor
35704 context-switches # 0.005 M/sec
191 CPU-migrations # 0.000 M/sec
8958 page-faults # 0.001 M/sec
<not counted> cycles
<not counted> instructions
<not counted> cache-references
<not counted> cache-misses

Wall-clock time elapsed: 1699.999995 msecs

Also add -v (--verbose) option to allow the printing of failed
counter opens.

Plus dont print 'inf' if wall-time is zero (due to jiffies granularity),
instead skip the printing of the CPU utilization factor.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
tools/perf/builtin-stat.c | 31 +++++++++++++++++--------------
1 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 2cbf5a1..184ff95 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -59,6 +59,7 @@ static struct perf_counter_attr default_attrs[MAX_COUNTERS] = {

static int system_wide = 0;
static int inherit = 1;
+static int verbose = 0;

static int fd[MAX_NR_CPUS][MAX_COUNTERS];

@@ -83,7 +84,7 @@ static __u64 event_scaled[MAX_COUNTERS];
static __u64 runtime_nsecs;
static __u64 walltime_nsecs;

-static void create_perfstat_counter(int counter)
+static void create_perf_stat_counter(int counter)
{
struct perf_counter_attr *attr = attrs + counter;

@@ -95,10 +96,8 @@ static void create_perfstat_counter(int counter)
int cpu;
for (cpu = 0; cpu < nr_cpus; cpu ++) {
fd[cpu][counter] = sys_perf_counter_open(attr, -1, cpu, -1, 0);
- if (fd[cpu][counter] < 0) {
- printf("perfstat error: syscall returned with %d (%s)\n",
- fd[cpu][counter], strerror(errno));
- exit(-1);
+ if (fd[cpu][counter] < 0 && verbose) {
+ printf("Error: counter %d, sys_perf_counter_open() syscall returned with %d (%s)\n", counter, fd[cpu][counter], strerror(errno));
}
}
} else {
@@ -106,10 +105,8 @@ static void create_perfstat_counter(int counter)
attr->disabled = 1;

fd[0][counter] = sys_perf_counter_open(attr, 0, -1, -1, 0);
- if (fd[0][counter] < 0) {
- printf("perfstat error: syscall returned with %d (%s)\n",
- fd[0][counter], strerror(errno));
- exit(-1);
+ if (fd[0][counter] < 0 && verbose) {
+ printf("Error: counter %d, sys_perf_counter_open() syscall returned with %d (%s)\n", counter, fd[0][counter], strerror(errno));
}
}
}
@@ -147,6 +144,9 @@ static void read_counter(int counter)

nv = scale ? 3 : 1;
for (cpu = 0; cpu < nr_cpus; cpu ++) {
+ if (fd[cpu][counter] < 0)
+ continue;
+
res = read(fd[cpu][counter], single_count, nv * sizeof(__u64));
assert(res == nv * sizeof(__u64));

@@ -204,8 +204,9 @@ static void print_counter(int counter)
if (attrs[counter].type == PERF_TYPE_SOFTWARE &&
attrs[counter].config == PERF_COUNT_TASK_CLOCK) {

- fprintf(stderr, " # %11.3f CPU utilization factor",
- (double)count[0] / (double)walltime_nsecs);
+ if (walltime_nsecs)
+ fprintf(stderr, " # %11.3f CPU utilization factor",
+ (double)count[0] / (double)walltime_nsecs);
}
} else {
fprintf(stderr, " %14Ld %-20s",
@@ -220,7 +221,7 @@ static void print_counter(int counter)
fprintf(stderr, "\n");
}

-static int do_perfstat(int argc, const char **argv)
+static int do_perf_stat(int argc, const char **argv)
{
unsigned long long t0, t1;
int counter;
@@ -232,7 +233,7 @@ static int do_perfstat(int argc, const char **argv)
nr_cpus = 1;

for (counter = 0; counter < nr_counters; counter++)
- create_perfstat_counter(counter);
+ create_perf_stat_counter(counter);

/*
* Enable counters and exec the command:
@@ -305,6 +306,8 @@ static const struct option options[] = {
"system-wide collection from all CPUs"),
OPT_BOOLEAN('S', "scale", &scale,
"scale/normalize counters"),
+ OPT_BOOLEAN('v', "verbose", &verbose,
+ "be more verbose (show counter open errors, etc)"),
OPT_END()
};

@@ -335,5 +338,5 @@ int cmd_stat(int argc, const char **argv, const char *prefix)
signal(SIGALRM, skip_signal);
signal(SIGABRT, skip_signal);

- return do_perfstat(argc, argv);
+ return do_perf_stat(argc, argv);
}