perf_counter: tools: Better handle existing data files

Provide an argument (-f) to overwrite existing data files.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/Documentation/perf_counter/builtin-record.c b/Documentation/perf_counter/builtin-record.c
index 810fc27..bace7a8 100644 (file)
--- a/Documentation/perf_counter/builtin-record.c
+++ b/Documentation/perf_counter/builtin-record.c
@@ -7,6 +7,7 @@
 #include "util/parse-events.h"
 #include "util/string.h"
 
+#include <unistd.h>
 #include <sched.h>
 
 #define ALIGN(x, a)            __ALIGN_MASK(x, (typeof(x))(a)-1)
@@ -26,7 +27,7 @@ static unsigned int           realtime_prio                   = 0;
 static int                     system_wide                     = 0;
 static pid_t                   target_pid                      = -1;
 static int                     inherit                         = 1;
-static int                     nmi                             = 1;
+static int                     force                           = 0;
 
 const unsigned int default_count[] = {
        1000000,
@@ -337,7 +338,6 @@ static void open_counters(int cpu, pid_t pid)
                hw_event.config         = event_id[counter];
                hw_event.irq_period     = event_count[counter];
                hw_event.record_type    = PERF_RECORD_IP | PERF_RECORD_TID;
-               hw_event.nmi            = nmi;
                hw_event.mmap           = track;
                hw_event.comm           = track;
                hw_event.inherit        = (cpu < 0) && inherit;
@@ -387,13 +387,20 @@ static int __cmd_record(int argc, const char **argv)
        int i, counter;
        pid_t pid;
        int ret;
+       struct stat st;
 
        page_size = sysconf(_SC_PAGE_SIZE);
        nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
        assert(nr_cpus <= MAX_NR_CPUS);
        assert(nr_cpus >= 0);
 
-       output = open(output_name, O_CREAT|O_EXCL|O_TRUNC|O_RDWR, S_IRUSR|S_IWUSR);
+       if (!stat(output_name, &st) && !force) {
+               fprintf(stderr, "Error, output file: %s exists, use -f to overwrite.\n",
+                               output_name);
+               exit(-1);
+       }
+
+       output = open(output_name, O_CREAT|O_TRUNC|O_RDWR, S_IRUSR|S_IWUSR);
        if (output < 0) {
                perror("failed to create output file");
                exit(-1);
@@ -473,6 +480,8 @@ static const struct option options[] = {
                    "collect data with this RT SCHED_FIFO priority"),
        OPT_BOOLEAN('a', "all-cpus", &system_wide,
                            "system-wide collection from all CPUs"),
+       OPT_BOOLEAN('f', "force", &force,
+                       "overwrite existing data file"),
        OPT_END()
 };