Add a couple of performance debug utilities.

micro_bench provides very simple tests for
o sleep accuracy
o cpu
o memcpy
o memset

sane_schedstat is a front-end for /proc/schedstat to diff and format the
counters.

Change-Id: I6e178fe37fcfc9bf0a83ec17852e31146a91e7a4
Signed-off-by: Nick Pelly <npelly@google.com>

2 files changed, 168 insertions, 0 deletions

diff --git a/sane_schedstat/Android.mk b/sane_schedstat/Android.mk
new file mode 100644
index 00000000..5843c43f
--- /dev/null
+++ b/sane_schedstat/Android.mk
@@ -0,0 +1,11 @@
+LOCAL_PATH:= $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := sane_schedstat.c
+
+LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
+LOCAL_MODULE_TAGS := debug
+LOCAL_MODULE := sane_schedstat
+
+include $(BUILD_EXECUTABLE)
diff --git a/sane_schedstat/sane_schedstat.c b/sane_schedstat/sane_schedstat.c
new file mode 100644
index 00000000..29d10633
--- /dev/null
+++ b/sane_schedstat/sane_schedstat.c
@@ -0,0 +1,157 @@
+/*
+** Copyright 2010 The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+
+/* Opens /proc/sched_stat and diff's the counters.
+   Currently support version 15, modify parse() to support other
+   versions
+*/
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <sys/uio.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <fcntl.h>
+
+#define MAX_CPU 2
+
+struct cpu_stat {
+    /* sched_yield() stats */
+    unsigned int yld_count;  /* sched_yield() called */
+
+    /* schedule() stats */
+    unsigned int sched_switch;  /* switched to expired queue and reused it */
+    unsigned int sched_count;  /* schedule() called */
+    unsigned int sched_goidle;  /* schedule() left the cpu idle */
+
+    /* try_to_wake_up() stats */
+    unsigned int ttwu_count;  /* try_to_wake_up() called */
+    /* try_to_wake_up() called and found the process being awakened last ran on
+     * the waking cpu */
+    unsigned int ttwu_local;
+
+    /* latency stats */
+    unsigned long long cpu_time;  /* time spent running by tasks (ms) */
+    unsigned long long run_delay; /* time spent waiting to run by tasks (ms) */
+    unsigned long pcount;  /* number of tasks (not necessarily unique) given */
+};
+
+struct cpu_stat cpu_prev[MAX_CPU];
+struct cpu_stat cpu_delta[MAX_CPU];
+struct cpu_stat tmp;
+
+static const char *next_line(const char *b) {
+    while (1) {
+        switch (*b) {
+        case '\n':
+            return b + 1;
+        case '\0':
+            return NULL;
+        }
+        b++;
+    }
+}
+static int print() {
+    int i;
+
+    printf("CPU  yield() schedule() switch idle   ttwu() local  cpu_time wait_time timeslices\n");
+    for (i=0; i<MAX_CPU; i++) {
+        printf(" %2d  %7u %10u %6u %4u %8u %5u %9llu %9llu %10lu\n",
+            i,
+            cpu_delta[i].yld_count,
+            cpu_delta[i].sched_count, cpu_delta[i].sched_switch, cpu_delta[i].sched_goidle,
+            cpu_delta[i].ttwu_count, cpu_delta[i].ttwu_local,
+            cpu_delta[i].cpu_time / 1000000, cpu_delta[i].run_delay / 1000000, cpu_delta[i].pcount);
+    }
+    return 0;
+}
+
+static int parse_cpu_v15(const char *b) {
+    int cpu;
+
+    if (sscanf(b, "cpu%d %u %u %u %u %u %u %llu %llu %lu\n",
+            &cpu, &tmp.yld_count,
+            &tmp.sched_switch, &tmp.sched_count, &tmp.sched_goidle,
+            &tmp.ttwu_count, &tmp.ttwu_local,
+            &tmp.cpu_time, &tmp.run_delay, &tmp.pcount) != 10) {
+        printf("Could not parse %s\n", b);
+        return -1;
+    }
+
+    cpu_delta[cpu].yld_count = tmp.yld_count - cpu_prev[cpu].yld_count;
+    cpu_delta[cpu].sched_switch = tmp.sched_switch - cpu_prev[cpu].sched_switch;
+    cpu_delta[cpu].sched_count = tmp.sched_count - cpu_prev[cpu].sched_count;
+    cpu_delta[cpu].sched_goidle = tmp.sched_goidle - cpu_prev[cpu].sched_goidle;
+    cpu_delta[cpu].ttwu_count = tmp.ttwu_count - cpu_prev[cpu].ttwu_count;
+    cpu_delta[cpu].ttwu_local = tmp.ttwu_local - cpu_prev[cpu].ttwu_local;
+    cpu_delta[cpu].cpu_time = tmp.cpu_time - cpu_prev[cpu].cpu_time;
+    cpu_delta[cpu].run_delay = tmp.run_delay - cpu_prev[cpu].run_delay;
+    cpu_delta[cpu].pcount = tmp.pcount - cpu_prev[cpu].pcount;
+
+    cpu_prev[cpu] = tmp;
+    return 0;
+}
+
+
+static int parse(const char *b) {
+    unsigned int version;
+    unsigned long long ts;
+
+    if (sscanf(b, "version %u\n", &version) != 1) {
+        printf("Could not parse version\n");
+        return -1;
+    }
+    switch (version) {
+    case 15:
+        b = next_line(b);
+        if (!b || sscanf(b, "timestamp %llu\n", &ts) != 1) {
+            printf("Could not parse timestamp\n");
+            return -1;
+        }
+        while (1) {
+            b = next_line(b);
+            if (!b) break;
+            if (b[0] == 'c') {
+                if (parse_cpu_v15(b)) return -1;
+            }
+        }
+        break;
+    default:
+        printf("Can not handle version %u\n", version);
+        return -1;
+    }
+    return 0;
+}
+
+int main(int argc, char **argv) {
+    int i;
+    int fd;
+    char buf[4096];
+
+    while (1) {
+        fd = open("/proc/schedstat", O_RDONLY);
+        if (fd < 0) return -1;
+        i = read(fd, buf, sizeof(buf) - 1);
+        close(fd);
+        buf[i] = '\0';
+        if (parse(buf)) return -1;
+        print();
+        sleep(1);
+    }
+    return 0;
+}