144 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			144 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C
		
	
	
	
/*
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 * Copyright (c) 2015 Eugene Syromyatnikov <evgsyr@gmail.com>
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 * Copyright (c) 2015-2016 Dmitry V. Levin <ldv@altlinux.org>
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 * Copyright (c) 2015-2017 The strace developers.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. The name of the author may not be used to endorse or promote products
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 *    derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/**
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 * @file
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 * This test burns some CPU cycles in user space and kernel space in order to
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 * get some non-zero values returned by times(2).
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 */
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#include "tests.h"
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#include <sched.h>
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#include <stdio.h>
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#include <time.h>
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#include <unistd.h>
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#include <asm/unistd.h>
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#include <sys/times.h>
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#include <sys/wait.h>
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enum {
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	NUM_USER_ITERS = 1000000,
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	PARENT_CPUTIME_LIMIT_NSEC = 200000000,
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	CHILD_CPUTIME_LIMIT_NSEC = 300000000
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};
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int
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main(void)
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{
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	struct timespec ts;
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	volatile int dummy = 0;
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	int i = 0;
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	pid_t pid = fork();
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	if (pid < 0)
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		perror_msg_and_fail("fork");
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	const long cputime_limit =
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		pid ? PARENT_CPUTIME_LIMIT_NSEC : CHILD_CPUTIME_LIMIT_NSEC;
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	/* Enjoying my user time */
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	while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
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		if (ts.tv_sec || ts.tv_nsec >= cputime_limit)
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			break;
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		if (i && !(ts.tv_sec || ts.tv_nsec))
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			error_msg_and_skip("clock_gettime(CLOCK_PROCESS_CPUTIME_ID, {0, 0})");
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		for (i = 0; i < NUM_USER_ITERS; ++i)
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			++dummy;
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	}
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	/* Enjoying my system time */
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	while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
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		if (ts.tv_sec || ts.tv_nsec >= cputime_limit * 2)
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			break;
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		sched_yield();
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	}
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	if (pid == 0) {
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		return 0;
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	} else {
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		wait(NULL);
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	}
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	struct tms tbuf;
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	unsigned long long llres;
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	/*
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	 * On systems where user's and kernel's long types are the same,
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	 * prefer direct times syscall over libc's times function because
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	 * the latter is more prone to return value truncation.
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	 */
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#undef USE_LIBC_SYSCALL
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#if defined __NR_times && \
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   !defined(LINUX_MIPSN32) && \
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   !(defined __x86_64__ && defined __ILP32__)
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# define USE_LIBC_SYSCALL 1
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#endif
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#if defined USE_LIBC_SYSCALL
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	long res = syscall(__NR_times, &tbuf);
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	if (-1L == res)
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		perror_msg_and_skip("times");
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	else
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		llres = (unsigned long) res;
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#elif defined __NR_times && defined __x86_64__ && defined __ILP32__
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	register long arg asm("rdi") = (long) &tbuf;
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	asm volatile("syscall\n\t"
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		     : "=a"(llres)
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		     : "0"(__NR_times), "r"(arg)
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		     : "memory", "cc", "r11", "cx");
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	if (llres > 0xfffffffffffff000)
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		return 77;
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#else
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	clock_t res = times(&tbuf);
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	if ((clock_t) -1 == res)
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		perror_msg_and_skip("times");
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	if (sizeof(res) < sizeof(unsigned long long))
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		llres = (unsigned long) res;
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	else
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		llres = res;
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#endif
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	printf("times({tms_utime=%llu, tms_stime=%llu, ",
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		(unsigned long long) tbuf.tms_utime,
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		(unsigned long long) tbuf.tms_stime);
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	printf("tms_cutime=%llu, tms_cstime=%llu}) = %llu\n",
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		(unsigned long long) tbuf.tms_cutime,
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		(unsigned long long) tbuf.tms_cstime,
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		llres);
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	puts("+++ exited with 0 +++");
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	return 0;
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}
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