[PATCH] blkparse: add stopwatch functionality

Like the blktrace -w option, but allow for defining an interval as well.

diff --git a/blkparse.c b/blkparse.c
index b3172f1d3ac1d790137cbbf3787807a853c7c0f8..891f96dbc566004532a3480eca2b7e6f09e7d60e 100644 (file)
--- a/blkparse.c
+++ b/blkparse.c
@@ -29,12 +29,14 @@
 #include <errno.h>
 #include <signal.h>
 #include <locale.h>
+#include <limits.h>
 
 #include "blktrace.h"
 #include "rbtree.h"
 
 #define SECONDS(x)             ((unsigned long long)(x) / 1000000000)
 #define NANO_SECONDS(x)                ((unsigned long long)(x) % 1000000000)
+#define DOUBLE_TO_NANO_ULL(d)  ((unsigned long long)((d) * 1000000000))
 
 #define MINORBITS      20
 #define MINORMASK      ((1U << MINORBITS) - 1)
@@ -91,7 +93,7 @@ struct per_process_info {
 static struct per_process_info *ppi_hash[1 << PPI_HASH_SHIFT];
 static struct per_process_info *ppi_list;
 
-#define S_OPTS "i:o:b:stq"
+#define S_OPTS "i:o:b:stqw:"
 static struct option l_opts[] = {
        {
                .name = "input",
@@ -129,6 +131,12 @@ static struct option l_opts[] = {
                .flag = NULL,
                .val = 'q'
        },
+       {
+               .name = "stopwatch",
+               .has_arg = 1,
+               .flag = NULL,
+               .val = 'w'
+       },
        {
                .name = NULL,
                .has_arg = 0,
@@ -171,6 +179,8 @@ static FILE *ofp;
 static char *output_name;
 
 static unsigned long long genesis_time;
+static unsigned long long stopwatch_start;     /* start from zero by default */
+static unsigned long long stopwatch_end = ULONG_LONG_MAX;      /* "infinity" */
 
 static int per_process_stats;
 static int track_ios;
@@ -1104,6 +1114,10 @@ static void show_entries_rb(void)
                }
 
                bit->time -= genesis_time;
+               if (bit->time < stopwatch_start)
+                       continue;
+               if (bit->time >= stopwatch_end)
+                       break;
 
                check_time(pdi, bit);
 
@@ -1305,10 +1319,43 @@ static void handle_sigint(int sig)
        flush_output();
 }
 
+/*
+ * Extract start and duration times from a string, allowing
+ * us to specify a time interval of interest within a trace.
+ * Format: "duration" (start is zero) or "start:duration".
+ */
+static int find_stopwatch_interval(char *string)
+{
+       double value;
+       char *sp;
+
+       value = strtod(string, &sp);
+       if (sp == string) {
+               fprintf(stderr,"Invalid stopwatch timer: %s\n", string);
+               return 1;
+       }
+       if (*sp == ':') {
+               stopwatch_start = DOUBLE_TO_NANO_ULL(value);
+               string = sp + 1;
+               value = strtod(string, &sp);
+               if (sp == string || *sp != '\0') {
+                       fprintf(stderr,"Invalid stopwatch duration time: %s\n",
+                               string);
+                       return 1;
+               }
+       } else if (*sp != '\0') {
+               fprintf(stderr,"Invalid stopwatch start timer: %s\n", string);
+               return 1;
+       }
+       stopwatch_end = stopwatch_start + DOUBLE_TO_NANO_ULL(value);
+       return 0;
+}
+
 static void usage(char *prog)
 {
-       fprintf(stderr, "Usage: %s [-i <name>] [-o <output>] [-s] <name>...\n",
-                       prog);
+       fprintf(stderr, "Usage: %s "
+               "[-i <name>] [-o <output>] [-s] [-w N[:n]] <name>...\n",
+               prog);
 }
 
 int main(int argc, char *argv[])
@@ -1342,6 +1389,10 @@ int main(int argc, char *argv[])
                case 'q':
                        per_device_and_cpu_stats = 0;
                        break;
+               case 'w':
+                       if (find_stopwatch_interval(optarg) != 0)
+                               return 1;
+                       break;
                default:
                        usage(argv[0]);
                        return 1;

diff --git a/btrace b/btrace
old mode 100644 (file)
new mode 100755 (executable)