perf: Make -f the default for perf record

Force the overwriting mode by default if append mode is not explicit.
Adding -f every time one uses perf on a daily basis quickly becomes a
burden.

Keep the -f among the options though to avoid breaking some random
users scripts.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 26 insertions, 16 deletions

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index fc46c0b40f6e..b29bd2db6a49 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -58,7 +58,7 @@ OPTIONS
 
 -f::
 --force::
-        Overwrite existing data file.
+        Overwrite existing data file. (deprecated)
 
 -c::
 --count=::
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 9a9513687235..dcda8993082d 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -26,6 +26,11 @@
 #include <unistd.h>
 #include <sched.h>
 
+enum write_mode_t {
+        WRITE_FORCE,
+        WRITE_APPEND
+};
+
 static int                      *fd[MAX_NR_CPUS][MAX_COUNTERS];
 
 static long                     default_interval                =      0;
@@ -47,8 +52,7 @@ static pid_t			*all_tids			=      NULL;
 static int                      thread_num                      =      0;
 static pid_t                    child_pid                       =     -1;
 static bool                     inherit                         =   true;
-static bool                     force                           =  false;
-static bool                     append_file                     =  false;
+static enum write_mode_t        write_mode                      = WRITE_FORCE;
 static bool                     call_graph                      =  false;
 static bool                     inherit_stat                    =  false;
 static bool                     no_samples                      =  false;
@@ -450,26 +454,19 @@ static int __cmd_record(int argc, const char **argv)
         }
 
         if (!stat(output_name, &st) && st.st_size) {
-                if (!force) {
-                        if (!append_file) {
-                                pr_err("Error, output file %s exists, use -A "
-                                       "to append or -f to overwrite.\n",
-                                       output_name);
-                                exit(-1);
-                        }
-                } else {
+                if (write_mode == WRITE_FORCE) {
                         char oldname[PATH_MAX];
                         snprintf(oldname, sizeof(oldname), "%s.old",
                                  output_name);
                         unlink(oldname);
                         rename(output_name, oldname);
                 }
-        } else {
-                append_file = false;
+        } else if (write_mode == WRITE_APPEND) {
+                write_mode = WRITE_FORCE;
         }
 
         flags = O_CREAT|O_RDWR;
-        if (append_file)
+        if (write_mode == WRITE_APPEND)
                 file_new = 0;
         else
                 flags |= O_TRUNC;
@@ -480,7 +477,8 @@ static int __cmd_record(int argc, const char **argv)
                 exit(-1);
         }
 
-        session = perf_session__new(output_name, O_WRONLY, force);
+        session = perf_session__new(output_name, O_WRONLY,
+                                    write_mode == WRITE_FORCE);
         if (session == NULL) {
                 pr_err("Not enough memory for reading perf file header\n");
                 return -1;
@@ -667,6 +665,8 @@ static const char * const record_usage[] = {
         NULL
 };
 
+static bool force, append_file;
+
 static const struct option options[] = {
         OPT_CALLBACK('e', "event", NULL, "event",
                      "event selector. use 'perf list' to list available events",
@@ -688,7 +688,7 @@ static const struct option options[] = {
         OPT_INTEGER('C', "profile_cpu", &profile_cpu,
                             "CPU to profile on"),
         OPT_BOOLEAN('f', "force", &force,
-                        "overwrite existing data file"),
+                        "overwrite existing data file (deprecated)"),
         OPT_LONG('c', "count", &default_interval,
                     "event period to sample"),
         OPT_STRING('o', "output", &output_name, "file",
@@ -725,6 +725,16 @@ int cmd_record(int argc, const char **argv, const char *prefix __used)
                 !system_wide && profile_cpu == -1)
                 usage_with_options(record_usage, options);
 
+        if (force && append_file) {
+                fprintf(stderr, "Can't overwrite and append at the same time."
+                                " You need to choose between -f and -A");
+                usage_with_options(record_usage, options);
+        } else if (append_file) {
+                write_mode = WRITE_APPEND;
+        } else {
+                write_mode = WRITE_FORCE;
+        }
+
         symbol__init();
 
         if (!nr_counters) {