1/*
2** Copyright 2010 The Android Open Source Project
3**
4** Licensed under the Apache License, Version 2.0 (the "License");
5** you may not use this file except in compliance with the License.
6** You may obtain a copy of the License at
7**
8**     http://www.apache.org/licenses/LICENSE-2.0
9**
10** Unless required by applicable law or agreed to in writing, software
11** distributed under the License is distributed on an "AS IS" BASIS,
12** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13** See the License for the specific language governing permissions and
14** limitations under the License.
15*/
16
17
18/* Opens /proc/sched_stat and diff's the counters.
19   Currently support version 15, modify parse() to support other
20   versions
21*/
22
23#include <stdlib.h>
24#include <stdio.h>
25#include <errno.h>
26#include <sys/uio.h>
27#include <unistd.h>
28#include <sys/time.h>
29#include <fcntl.h>
30
31#define MAX_CPU 2
32
33struct cpu_stat {
34    /* sched_yield() stats */
35    unsigned int yld_count;  /* sched_yield() called */
36
37    /* schedule() stats */
38    unsigned int sched_switch;  /* switched to expired queue and reused it */
39    unsigned int sched_count;  /* schedule() called */
40    unsigned int sched_goidle;  /* schedule() left the cpu idle */
41
42    /* try_to_wake_up() stats */
43    unsigned int ttwu_count;  /* try_to_wake_up() called */
44    /* try_to_wake_up() called and found the process being awakened last ran on
45     * the waking cpu */
46    unsigned int ttwu_local;
47
48    /* latency stats */
49    unsigned long long cpu_time;  /* time spent running by tasks (ms) */
50    unsigned long long run_delay; /* time spent waiting to run by tasks (ms) */
51    unsigned long pcount;  /* number of tasks (not necessarily unique) given */
52};
53
54struct cpu_stat cpu_prev[MAX_CPU];
55struct cpu_stat cpu_delta[MAX_CPU];
56struct cpu_stat tmp;
57
58static const char *next_line(const char *b) {
59    while (1) {
60        switch (*b) {
61        case '\n':
62            return b + 1;
63        case '\0':
64            return NULL;
65        }
66        b++;
67    }
68}
69static int print() {
70    int i;
71
72    printf("CPU  yield() schedule() switch idle   ttwu() local  cpu_time wait_time timeslices\n");
73    for (i=0; i<MAX_CPU; i++) {
74        printf(" %2d  %7u %10u %6u %4u %8u %5u %9llu %9llu %10lu\n",
75            i,
76            cpu_delta[i].yld_count,
77            cpu_delta[i].sched_count, cpu_delta[i].sched_switch, cpu_delta[i].sched_goidle,
78            cpu_delta[i].ttwu_count, cpu_delta[i].ttwu_local,
79            cpu_delta[i].cpu_time / 1000000, cpu_delta[i].run_delay / 1000000, cpu_delta[i].pcount);
80    }
81    return 0;
82}
83
84static int parse_cpu_v15(const char *b) {
85    int cpu;
86
87    if (sscanf(b, "cpu%d %u %u %u %u %u %u %llu %llu %lu\n",
88            &cpu, &tmp.yld_count,
89            &tmp.sched_switch, &tmp.sched_count, &tmp.sched_goidle,
90            &tmp.ttwu_count, &tmp.ttwu_local,
91            &tmp.cpu_time, &tmp.run_delay, &tmp.pcount) != 10) {
92        printf("Could not parse %s\n", b);
93        return -1;
94    }
95
96    cpu_delta[cpu].yld_count = tmp.yld_count - cpu_prev[cpu].yld_count;
97    cpu_delta[cpu].sched_switch = tmp.sched_switch - cpu_prev[cpu].sched_switch;
98    cpu_delta[cpu].sched_count = tmp.sched_count - cpu_prev[cpu].sched_count;
99    cpu_delta[cpu].sched_goidle = tmp.sched_goidle - cpu_prev[cpu].sched_goidle;
100    cpu_delta[cpu].ttwu_count = tmp.ttwu_count - cpu_prev[cpu].ttwu_count;
101    cpu_delta[cpu].ttwu_local = tmp.ttwu_local - cpu_prev[cpu].ttwu_local;
102    cpu_delta[cpu].cpu_time = tmp.cpu_time - cpu_prev[cpu].cpu_time;
103    cpu_delta[cpu].run_delay = tmp.run_delay - cpu_prev[cpu].run_delay;
104    cpu_delta[cpu].pcount = tmp.pcount - cpu_prev[cpu].pcount;
105
106    cpu_prev[cpu] = tmp;
107    return 0;
108}
109
110
111static int parse(const char *b) {
112    unsigned int version;
113    unsigned long long ts;
114
115    if (sscanf(b, "version %u\n", &version) != 1) {
116        printf("Could not parse version\n");
117        return -1;
118    }
119    switch (version) {
120    case 15:
121        b = next_line(b);
122        if (!b || sscanf(b, "timestamp %llu\n", &ts) != 1) {
123            printf("Could not parse timestamp\n");
124            return -1;
125        }
126        while (1) {
127            b = next_line(b);
128            if (!b) break;
129            if (b[0] == 'c') {
130                if (parse_cpu_v15(b)) return -1;
131            }
132        }
133        break;
134    default:
135        printf("Can not handle version %u\n", version);
136        return -1;
137    }
138    return 0;
139}
140
141int main(int argc, char **argv) {
142    int i;
143    int fd;
144    char buf[4096];
145
146    while (1) {
147        fd = open("/proc/schedstat", O_RDONLY);
148        if (fd < 0) return -1;
149        i = read(fd, buf, sizeof(buf) - 1);
150        close(fd);
151        buf[i] = '\0';
152        if (parse(buf)) return -1;
153        print();
154        sleep(1);
155    }
156    return 0;
157}
158