/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 *	File:	vm_stat.c
 *	Author:	Avadis Tevanian, Jr.
 *
 *	Copyright (C) 1986, Avadis Tevanian, Jr.
 *
 *
 *	Display Mach VM statistics.
 *
 ************************************************************************
 * HISTORY
 *  6-Jun-86  Avadis Tevanian, Jr. (avie) at Carnegie-Mellon University
 *	Use official Mach interface.
 *
 *  25-mar-99	A.Ramesh at Apple
 *		Ported to MacOS X
 ************************************************************************
 */

#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>

#include <mach/mach.h>

vm_statistics_data_t	vm_stat, last;
natural_t percent;
int	delay;
char	*pgmname;
mach_port_t myHost;
int pageSize = 4096; 	/* set to 4k default */

void usage(void);
void banner(void);
void snapshot(void);
void pstat(char *str, natural_t n);
void print_stats(void);
void get_stats(struct vm_statistics *stat);

int
main(int argc, char *argv[])
{

	pgmname = argv[0];
	delay = 0;


	setlinebuf (stdout);

	if (argc == 2) {
		if (sscanf(argv[1], "%d", &delay) != 1)
			usage();
		if (delay < 0)
			usage();
	}

	myHost = mach_host_self();

	if(host_page_size(mach_host_self(), &pageSize) != KERN_SUCCESS) {
		fprintf(stderr, "%s: failed to get pagesize; defaulting to 4K.\n", pgmname);
		pageSize = 4096;
	}	

	if (delay == 0) {
		snapshot();
	}
	else {
		while (1) {
			print_stats();
			sleep(delay);
		}
	}
	exit(EXIT_SUCCESS);
}

void
usage(void)
{
	fprintf(stderr, "usage: %s [ repeat-interval ]\n", pgmname);
	exit(EXIT_FAILURE);
}

void
banner(void)
{
	get_stats(&vm_stat);
	printf("Mach Virtual Memory Statistics: ");
	printf("(page size of %d bytes, cache hits %u%%)\n",
				pageSize, percent);
	printf("%6s %6s %4s %4s %8s %8s %8s %8s %8s %8s\n",
		"free",
		"active",
		"inac",
		"wire",
		"faults",
		"copy",
		"zerofill",
		"reactive",
		"pageins",
		"pageout");
	bzero(&last, sizeof(last));
}

void
snapshot(void)
{

	get_stats(&vm_stat);
	printf("Mach Virtual Memory Statistics: (page size of %d bytes)\n",
				pageSize);

	pstat("Pages free:", vm_stat.free_count);
	pstat("Pages active:", vm_stat.active_count);
	pstat("Pages inactive:", vm_stat.inactive_count);
	pstat("Pages wired down:", vm_stat.wire_count);
	pstat("\"Translation faults\":", vm_stat.faults);
	pstat("Pages copy-on-write:", vm_stat.cow_faults);
	pstat("Pages zero filled:", vm_stat.zero_fill_count);
	pstat("Pages reactivated:", vm_stat.reactivations);
	pstat("Pageins:", vm_stat.pageins);
	pstat("Pageouts:", vm_stat.pageouts);
	printf("Object cache: %u hits of %u lookups (%u%% hit rate)\n",
			vm_stat.hits, vm_stat.lookups, percent);
}

void
pstat(char *str, natural_t n)
{
	printf("%-25s %10u.\n", str, n);
}

void
print_stats(void)
{
	static int count = 0;

	if (count++ == 0)
		banner();

	if (count > 20)
		count = 0;

	get_stats(&vm_stat);
	printf("%6u %6u %4u %4u %8u %8u %8u %8u %8u %8u\n",
		vm_stat.free_count,
		vm_stat.active_count,
		vm_stat.inactive_count,
		vm_stat.wire_count,
		vm_stat.faults - last.faults,
		vm_stat.cow_faults - last.cow_faults,
		vm_stat.zero_fill_count - last.zero_fill_count,
		vm_stat.reactivations - last.reactivations,
		vm_stat.pageins - last.pageins,
		vm_stat.pageouts - last.pageouts);
	last = vm_stat;
}

void
get_stats(struct vm_statistics *stat)
{
	int count = HOST_VM_INFO_COUNT;
	if (host_statistics(myHost, HOST_VM_INFO, (host_info_t)stat, &count) != KERN_SUCCESS) {
		fprintf(stderr, "%s: failed to get statistics.\n", pgmname);
		exit(EXIT_FAILURE);
	}
	if (stat->lookups == 0)
		percent = 0;
	else {
		/*
		 * We have limited precision with the 32-bit natural_t fields
		 * in the vm_statistics structure.  There's nothing we can do
		 * about counter overflows, but we can avoid percentage
		 * calculation overflows by doing the computation in floating
		 * point arithmetic ...
		 */
		percent = (natural_t)(((double)stat->hits*100)/stat->lookups);
	}
}