57 lines
1.6 KiB
C
57 lines
1.6 KiB
C
/*
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* Copyright (C) 2011 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Minimal test program for clock
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#include <unistd.h>
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// this thread soaks the CPU so that clock() function will advance
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void *cpu_hog(void *arg)
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{
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for (;;) {
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// the system call should not be optimized away by the compiler
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(void) getpid();
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}
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}
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int main(int argc, char **argv)
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{
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pthread_t thread;
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clock_t ticks10, ticks15;
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// do not call clock() here so we can test initialization
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// soak the CPU for 10 seconds, then read clock
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pthread_create(&thread, NULL, cpu_hog, NULL);
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sleep(10);
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ticks10 = clock();
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// soak the CPU for 5 more seconds, then read clock
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sleep(5);
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ticks15 = clock();
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// print the results
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printf("CLOCKS_PER_SEC = %ld ticks/sec\n", (clock_t) CLOCKS_PER_SEC);
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printf("At 10 secs clock=%lu, at 15 secs clock=%lu\n", ticks10, ticks15);
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// exit could wait for the other thread to complete
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_exit(EXIT_SUCCESS);
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}
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