path: root/kern/lock_mon.c

/*
 * Mach Operating System
 * Copyright (c) 1990 Carnegie-Mellon University
 * Copyright (c) 1989 Carnegie-Mellon University
 * All rights reserved.  The CMU software License Agreement specifies
 * the terms and conditions for use and redistribution.
 */
/*
 * Copyright 1990 by Open Software Foundation,
 * Grenoble, FRANCE
 *
 * 		All Rights Reserved
 *
 *   Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby granted,
 * provided that the above copyright notice appears in all copies and
 * that both the copyright notice and this permission notice appear in
 * supporting documentation, and that the name of OSF or Open Software
 * Foundation not be used in advertising or publicity pertaining to
 * distribution of the software without specific, written prior
 * permission.
 *
 *   OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
 * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
 * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * 	Support For MP Debugging
 *		if MACH_MP_DEBUG is on, we use alternate locking
 *		routines do detect dealocks
 *	Support for MP lock monitoring (MACH_LOCK_MON).
 *		Registers use of locks, contention.
 *		Depending on hardware also records time spent with locks held
 */

#include <sys/types.h>
#include <string.h>

#include <mach/machine/vm_types.h>
#include <mach/boolean.h>
#include <kern/thread.h>
#include <kern/lock.h>
#include <kern/time_stamp.h>


decl_simple_lock_data(extern , kdb_lock)
decl_simple_lock_data(extern , printf_lock)

#if	NCPUS > 1 && MACH_LOCK_MON

#if	TIME_STAMP
extern	time_stamp_t time_stamp;
#else	/* TIME_STAMP */
typedef unsigned int time_stamp_t;
#define	time_stamp 0
#endif	/* TIME_STAMP */

#define LOCK_INFO_MAX	     (1024*32)
#define LOCK_INFO_HASH_COUNT 1024
#define LOCK_INFO_PER_BUCKET	(LOCK_INFO_MAX/LOCK_INFO_HASH_COUNT)

#define HASH_LOCK(lock)	((long)lock>>5 & (LOCK_INFO_HASH_COUNT-1))

struct lock_info {
	unsigned int	success;
	unsigned int	fail;
	unsigned int	masked;
	unsigned int	stack;
	time_stamp_t	time;
	decl_simple_lock_data(, *lock)
	vm_offset_t	caller;
};

struct lock_info_bucket {
	struct lock_info info[LOCK_INFO_PER_BUCKET];
};

struct lock_info_bucket lock_info[LOCK_INFO_HASH_COUNT];
struct lock_info default_lock_info;
unsigned default_lock_stack = 0;

extern spl_t curr_ipl[];



struct lock_info *
locate_lock_info(lock)
decl_simple_lock_data(, **lock)
{
	struct lock_info *li =  &(lock_info[HASH_LOCK(*lock)].info[0]);
	int i;
	my_cpu = cpu_number();

	for (i=0; i < LOCK_INFO_PER_BUCKET; i++, li++)
		if (li->lock) {
			if (li->lock == *lock)
				return(li);
		} else {
			li->lock = *lock;
			li->caller = *((vm_offset_t *)lock - 1);
			return(li);
		}
	db_printf("out of lock_info slots\n");
	li = &default_lock_info;
	return(li);
}


void simple_lock(lock)
decl_simple_lock_data(, *lock)
{
	struct lock_info *li = locate_lock_info(&lock);
	my_cpu = cpu_number();

	if (current_thread())
		li->stack = current_thread()->lock_stack++;
	if (curr_ipl[my_cpu])
		li->masked++;
	if (_simple_lock_try(lock))
		li->success++;
	else {
		_simple_lock(lock);
		li->fail++;
	}
	li->time = time_stamp - li->time;
}

int simple_lock_try(lock)
decl_simple_lock_data(, *lock)
{
	struct lock_info *li = locate_lock_info(&lock);
	my_cpu = cpu_number();

	if (curr_ipl[my_cpu])
		li->masked++;
	if (_simple_lock_try(lock)) {
		li->success++;
		li->time = time_stamp - li->time;
		if (current_thread())
			li->stack = current_thread()->lock_stack++;
		return(1);
	} else {
		li->fail++;
		return(0);
	}
}

void simple_unlock(lock)
decl_simple_lock_data(, *lock)
{
	time_stamp_t stamp = time_stamp;
	time_stamp_t *time = &locate_lock_info(&lock)->time;
	unsigned *lock_stack;

	*time = stamp - *time;
	_simple_unlock(lock);
	if (current_thread()) {
		lock_stack = &current_thread()->lock_stack;
		if (*lock_stack)
			(*lock_stack)--;
	}
}

void lip(void) {
	lis(4, 1, 0);
}

#define lock_info_sort lis

void lock_info_sort(arg, abs, count)
{
	struct lock_info *li, mean;
	int bucket = 0;
	int i;
	unsigned max_val;
	unsigned old_val = (unsigned)-1;
	struct lock_info *target_li = &lock_info[0].info[0];
	unsigned sum;
	unsigned empty, total;
	unsigned curval;

	printf("\nSUCCESS	FAIL	MASKED	STACK	TIME	LOCK/CALLER\n");
	if (!count)
		count = 8 ;
	while (count && target_li) {
		empty = LOCK_INFO_HASH_COUNT;
		target_li = 0;
		total = 0;
		max_val = 0;
		mean.success = 0;
		mean.fail = 0;
		mean.masked = 0;
		mean.stack = 0;
		mean.time = 0;
		mean.lock = (simple_lock_data_t *) &lock_info;
		mean.caller = (vm_offset_t) &lock_info;
		for (bucket = 0; bucket < LOCK_INFO_HASH_COUNT; bucket++) {
			li = &lock_info[bucket].info[0];
			if (li->lock)
				empty--;
			for (i= 0; i< LOCK_INFO_PER_BUCKET && li->lock; i++, li++) {
				if (li->lock == &kdb_lock || li->lock == &printf_lock)
					continue;
				total++;
				curval = *((int *)li + arg);
				sum = li->success + li->fail;
				if(!sum && !abs)
					continue;
				if (!abs) switch(arg) {
				case 0:
					break;
				case 1:
				case 2:
					curval = (curval*100) / sum;
					break;
				case 3:
				case 4:
					curval = curval / sum;
					break;
				}
				if (curval > max_val && curval < old_val) {
					max_val = curval;
					target_li = li;
				}
				if (curval == old_val && count != 0) {
					print_lock_info(li);
					count--;
				}
				mean.success += li->success;
				mean.fail += li->fail;
				mean.masked += li->masked;
				mean.stack += li->stack;
				mean.time += li->time;
			}
		}
		if (target_li)
		        old_val = max_val;
	}
	db_printf("\n%d total locks, %d empty buckets", total, empty );
	if (default_lock_info.success)
		db_printf(", default: %d", default_lock_info.success + default_lock_info.fail);
	db_printf("\n");
	print_lock_info(&mean);
}

#define lock_info_clear lic

void lock_info_clear(void)
{
	struct lock_info *li;
	int bucket = 0;
	int i;
	for (bucket = 0; bucket < LOCK_INFO_HASH_COUNT; bucket++) {
		li = &lock_info[bucket].info[0];
		for (i= 0; i< LOCK_INFO_PER_BUCKET; i++, li++) {
			memset(li, 0, sizeof(struct lock_info));
		}
	}
	memset(&default_lock_info, 0, sizeof(struct lock_info));
}

void print_lock_info(li)
struct lock_info *li;
{
	int off;
	int sum = li->success + li->fail;
	db_printf("%d	%d/%d	%d/%d	%d/%d	%d/%d	", li->success,
		   li->fail, (li->fail*100)/sum,
		   li->masked, (li->masked*100)/sum,
		   li->stack, li->stack/sum,
		   li->time, li->time/sum);
	db_free_symbol(db_search_symbol(li->lock, 0, &off));
	if (off < 1024)
		db_printsym(li->lock, 0);
	else {
		db_printsym(li->caller, 0);
		db_printf("(%X)", li->lock);
	}
	db_printf("\n");
}

#endif	/* NCPUS > 1 && MACH_LOCK_MON */

#if	TIME_STAMP

/*
 *	Measure lock/unlock operations
 */

void time_lock(int loops)
{
	decl_simple_lock_data(, lock)
	time_stamp_t stamp;
	int i;


	if (!loops)
		loops = 1000;
	simple_lock_init(&lock);
	stamp = time_stamp;
	for (i = 0; i < loops; i++) {
		simple_lock(&lock);
		simple_unlock(&lock);
	}
	stamp = time_stamp - stamp;
	db_printf("%d stamps for simple_locks\n", stamp/loops);
#if	MACH_LOCK_MON
	stamp = time_stamp;
	for (i = 0; i < loops; i++) {
		_simple_lock(&lock);
		_simple_unlock(&lock);
        }
	stamp = time_stamp - stamp;
	db_printf("%d stamps for _simple_locks\n", stamp/loops);
#endif	/* MACH_LOCK_MON */
}
#endif	/* TIME_STAMP */

#if	MACH_MP_DEBUG

/*
 *	Arrange in the lock routines to call the following
 *	routines. This way, when locks are free there is no performance
 *	penalty
 */

void
retry_simple_lock(lock)
decl_simple_lock_data(, *lock)
{
	count = 0;

	while(!simple_lock_try(lock))
		if (count++ > 1000000 && lock != &kdb_lock) {
			if (lock == &printf_lock)
				return;
			db_printf("cpu %d looping on simple_lock(%x) called by %x\n",
				cpu_number(), lock, *(((int *)&lock) -1));
			SoftDebugger("simple_lock timeout");
			count = 0;
		}
}

void
retry_bit_lock(index, addr)
{
	count = 0;

	while(!bit_lock_try(index, addr))
		if (count++ > 1000000) {
			db_printf("cpu %d looping on bit_lock(%x, %x) called by %x\n",
				cpu_number(), index, addr, *(((int *)&index) -1));
			SoftDebugger("bit_lock timeout");
			count = 0;
		}
}
#endif	/* MACH_MP_DEBUG */