Changeset d6d6b3e in mainline for uspace/app/tester/ipc/ping_pong.c

Timestamp:

2018-11-02T10:35:43Z (5 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

e131bd05

Parents:

2e4343b

git-author:

Jiri Svoboda <jiri@…> (2018-11-01 22:34:53)

git-committer:

Jiri Svoboda <jiri@…> (2018-11-02 10:35:43)

Message:

IPC benchmark can be more precise and more scientific.

File:

• uspace/app/tester/ipc/ping_pong.c (modified) (2 diffs)

uspace/app/tester/ipc/ping_pong.c

@@ -27 +27 @@
  */
 
+#include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -35 +36 @@
 #include "../tester.h"
 
-#define DURATION_SECS      10
-#define COUNT_GRANULARITY  100
+#define MIN_DURATION_SECS  10
+#define NUM_SAMPLES 10
+
+static errno_t ping_pong_measure(uint64_t niter, uint64_t *rduration)
+{
+        struct timespec start;
+        uint64_t count;
+
+        getuptime(&start);
+
+        for (count = 0; count < niter; count++) {
+                errno_t retval = ns_ping();
+
+                if (retval != EOK) {
+                        TPRINTF("Error sending ping message.\n");
+                        return EIO;
+                }
+        }
+
+        struct timespec now;
+        getuptime(&now);
+
+        *rduration = ts_sub_diff(&now, &start) / 1000;
+        return EOK;
+}
+
+static void ping_pong_report(uint64_t niter, uint64_t duration)
+{
+        TPRINTF("Completed %" PRIu64 " round trips in %" PRIu64" us",
+            niter, duration);
+
+        if (duration > 0) {
+                TPRINTF(", %" PRIu64 " rt/s.\n", niter * 1000 * 1000 / duration);
+        } else {
+                TPRINTF(".\n");
+        }
+}
 
 const char *test_ping_pong(void)
 {
-        TPRINTF("Pinging ns server for %d seconds...", DURATION_SECS);
+        errno_t rc;
+        uint64_t duration;
+        uint64_t dsmp[NUM_SAMPLES];
+
+        TPRINTF("Benchmark ns server ping time\n");
+        TPRINTF("Warm up and determine work size...\n");
 
         struct timespec start;
         getuptime(&start);
 
-        uint64_t count = 0;
+        uint64_t niter = 1;
+
         while (true) {
-                struct timespec now;
-                getuptime(&now);
+                rc = ping_pong_measure(niter, &duration);
+                if (rc != EOK)
+                        return "Failed.";
 
-                if (NSEC2SEC(ts_sub_diff(&now, &start)) >= DURATION_SECS)
+                ping_pong_report(niter, duration);
+
+                if (duration >= MIN_DURATION_SECS * 1000000)
                         break;
 
-                size_t i;
-                for (i = 0; i < COUNT_GRANULARITY; i++) {
-                        errno_t retval = ns_ping();
-
-                        if (retval != EOK) {
-                                TPRINTF("\n");
-                                return "Failed to send ping message";
-                        }
-                }
-
-                count += COUNT_GRANULARITY;
+                niter *= 2;
         }
 
-        TPRINTF("OK\nCompleted %" PRIu64 " round trips in %u seconds, %" PRIu64 " rt/s.\n",
-            count, DURATION_SECS, count / DURATION_SECS);
+        TPRINTF("Measure %d samples...\n", NUM_SAMPLES);
+
+        int i;
+
+        for (i = 0; i < NUM_SAMPLES; i++) {
+                rc = ping_pong_measure(niter, &dsmp[i]);
+                if (rc != EOK)
+                        return "Failed.";
+
+                ping_pong_report(niter, dsmp[i]);
+        }
+
+        double sum = 0.0;
+
+        for (i = 0; i < NUM_SAMPLES; i++)
+                sum += (double)niter / ((double)dsmp[i] / 1000000.0l);
+
+        double avg = sum / NUM_SAMPLES;
+
+        double qd = 0.0;
+        double d;
+        for (i = 0; i < NUM_SAMPLES; i++) {
+                d = (double)niter / ((double)dsmp[i] / 1000000.0l) - avg;
+                qd += d*d;
+        }
+
+        double stddev = qd; // XXX sqrt
+
+        TPRINTF("Average: %.0f rt/s Std.dev^2: %.0f rt/s Samples: %d\n",
+            avg, stddev, NUM_SAMPLES);
 
         return NULL;