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/*
** 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;
}
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