1 files changed, 48 insertions, 3 deletions

diff --git a/trace-cmd.c b/trace-cmd.c
index 49110f3..e85b550 100644
--- a/trace-cmd.c
+++ b/trace-cmd.c
@@ -56,6 +56,8 @@ static int use_tcp;
 
 static unsigned int page_size;
 
+static int buffer_size;
+
 static const char *output_file = "trace.dat";
 
 static int latency;
@@ -1239,6 +1241,32 @@ static void add_func(struct func_list **list, const char *func)
         *list = item;
 }
 
+void set_buffer_size(void)
+{
+        char buf[BUFSIZ];
+        char *path;
+        int ret;
+        int fd;
+
+        if (!buffer_size)
+                return;
+
+        if (buffer_size < 0)
+                die("buffer size must be positive");
+
+        snprintf(buf, BUFSIZ, "%d", buffer_size);
+
+        path = get_tracing_file("buffer_size_kb");
+        fd = open(path, O_WRONLY);
+        if (fd < 0)
+                die("can't open %s", path);
+
+        ret = write(fd, buf, strlen(buf));
+        if (ret < 0)
+                warning("Can't write to %s", path);
+        close(fd);
+}
+
 void usage(char **argv)
 {
         char *arg = argv[0];
@@ -1253,7 +1281,7 @@ void usage(char **argv)
                "usage:\n"
                " %s record [-v][-e event [-f filter]][-p plugin][-F][-d][-o file] \\\n"
                "           [-s usecs][-O option ][-l func][-g func][-n func]\n"
-               "           [-P pid][-N host:port][-t][command ...]\n"
+               "           [-P pid][-N host:port][-t][-b size][command ...]\n"
                "          -e run command with event enabled\n"
                "          -f filter for previous -e event\n"
                "          -p run command with plugin enabled\n"
@@ -1269,6 +1297,7 @@ void usage(char **argv)
                "          -s sleep interval between recording (in usecs) [default: 1000]\n"
                "          -N host:port to connect to (see listen)\n"
                "          -t used with -N, forces use of tcp in live trace\n"
+               "          -b change kernel buffersize (in kilobytes per CPU)\n"
                "\n"
                " %s start [-e event][-p plugin][-d][-O option ][-P pid]\n"
                "          Uses same options as record, but does not run a command.\n"
@@ -1281,9 +1310,10 @@ void usage(char **argv)
                "          Stops the tracer from recording more data.\n"
                "          Used in conjunction with start\n"
                "\n"
-               " %s reset\n"
+               " %s reset [-b size]\n"
                "          Disables the tracer (may reset trace file)\n"
                "          Used in conjunction with start\n"
+               "          -b change the kernel buffer size (in kilobytes per CPU)\n"
                "\n"
                " %s report [-i file] [--cpu cpu] [-e][-f][-l][-P][-E][-F filter][-v]\n"
                "          -i input file [default trace.dat]\n"
@@ -1364,7 +1394,7 @@ int main (int argc, char **argv)
                    (strcmp(argv[1], "start") == 0) ||
                    ((extract = strcmp(argv[1], "extract") == 0))) {
 
-                while ((c = getopt(argc-1, argv+1, "+he:f:Fp:do:O:s:vg:l:n:P:N:t")) >= 0) {
+                while ((c = getopt(argc-1, argv+1, "+he:f:Fp:do:O:s:vg:l:n:P:N:tb:")) >= 0) {
                         switch (c) {
                         case 'h':
                                 usage(argv);
@@ -1467,6 +1497,9 @@ int main (int argc, char **argv)
                         case 't':
                                 use_tcp = 1;
                                 break;
+                        case 'b':
+                                buffer_size = atoi(optarg);
+                                break;
                         }
                 }
 
@@ -1475,7 +1508,18 @@ int main (int argc, char **argv)
                 exit(0);
 
         } else if (strcmp(argv[1], "reset") == 0) {
+                while ((c = getopt(argc-1, argv+1, "b:")) >= 0) {
+                        switch (c) {
+                        case 'b':
+                                buffer_size = atoi(optarg);
+                                /* Min buffer size is 1 */
+                                if (strcmp(optarg, "0") == 0)
+                                        buffer_size = 1;
+                                break;
+                        }
+                }
                 disable_all();
+                set_buffer_size();
                 exit(0);
 
         } else if (strcmp(argv[1], "list") == 0) {
@@ -1547,6 +1591,7 @@ int main (int argc, char **argv)
 
                 if (events)
                         enable_events();
+                set_buffer_size();
         }
 
         if (plugin) {