profiling: write "correct" sample rate to gmon output

This duration vs sample count is _significantly_ closer to the truth
than simply declaring the value to be 100Hz.

Change-Id: Ie8d8bdf1959e1aa7cead0631cd2c86afe77d1efc
Signed-off-by: Karl Palsson <karlp@tweak.net.au>
Reviewed-on: http://openocd.zylin.com/4221
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

diff --git a/src/target/target.c b/src/target/target.c
index a9907b0c3ef92f042dd11d5495084a7fe6419a47..d6781a3c4e087f16ad825709820ef04d7b220f4e 100644 (file)
--- a/src/target/target.c
+++ b/src/target/target.c
@@ -3838,7 +3838,7 @@ typedef unsigned char UNIT[2];  /* unit of profiling */
 
 /* Dump a gmon.out histogram file. */
 static void write_gmon(uint32_t *samples, uint32_t sampleNum, const char *filename, bool with_range,
-                       uint32_t start_address, uint32_t end_address, struct target *target)
+                       uint32_t start_address, uint32_t end_address, struct target *target, uint32_t duration_ms)
 {
        uint32_t i;
        FILE *f = fopen(filename, "w");
@@ -3906,7 +3906,8 @@ static void write_gmon(uint32_t *samples, uint32_t sampleNum, const char *filena
        writeLong(f, min, target);                      /* low_pc */
        writeLong(f, max, target);                      /* high_pc */
        writeLong(f, numBuckets, target);       /* # of buckets */
-       writeLong(f, 100, target);                      /* KLUDGE! We lie, ca. 100Hz best case. */
+       float sample_rate = sampleNum / (duration_ms / 1000.0);
+       writeLong(f, sample_rate, target);
        writeString(f, "seconds");
        for (i = 0; i < (15-strlen("seconds")); i++)
                writeData(f, &zero, 1);
@@ -3955,6 +3956,7 @@ COMMAND_HANDLER(handle_profile_command)
                return ERROR_FAIL;
        }
 
+       uint64_t timestart_ms = timeval_ms();
        /**
         * Some cores let us sample the PC without the
         * annoying halt/resume step; for example, ARMv7 PCSR.
@@ -3966,6 +3968,7 @@ COMMAND_HANDLER(handle_profile_command)
                free(samples);
                return retval;
        }
+       uint32_t duration_ms = timeval_ms() - timestart_ms;
 
        assert(num_of_samples <= MAX_PROFILE_SAMPLE_NUM);
 
@@ -3998,7 +4001,7 @@ COMMAND_HANDLER(handle_profile_command)
        }
 
        write_gmon(samples, num_of_samples, CMD_ARGV[1],
-                  with_range, start_address, end_address, target);
+                  with_range, start_address, end_address, target, duration_ms);
        command_print(CMD_CTX, "Wrote %s", CMD_ARGV[1]);
 
        free(samples);