[dragonfly.git] / sys / kern / subr_prof.c

/*-
 * Copyright (c) 1982, 1986, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)subr_prof.c	8.3 (Berkeley) 9/23/93
 * $FreeBSD: src/sys/kern/subr_prof.c,v 1.32.2.2 2000/08/03 00:09:32 ps Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sysctl.h>

#include <sys/thread2.h>
#include <sys/mplock2.h>

#include <machine/cpu.h>

#ifdef GPROF
#include <sys/malloc.h>
#include <sys/gmon.h>
#undef MCOUNT

static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");

static void kmstartup (void *);
SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL)

struct gmonparam _gmonparam = { GMON_PROF_OFF };

#ifdef GUPROF
#include <machine/asmacros.h>

void
nullfunc_loop_profiled(void)
{
	int i;

	for (i = 0; i < CALIB_SCALE; i++)
		nullfunc_profiled();
}

#define	nullfunc_loop_profiled_end	nullfunc_profiled	/* XXX */

void
nullfunc_profiled(void)
{
}
#endif /* GUPROF */

static void
kmstartup(void *dummy)
{
	char *cp;
	struct gmonparam *p = &_gmonparam;
#ifdef GUPROF
	int cputime_overhead;
	int empty_loop_time;
	int i;
	int mcount_overhead;
	int mexitcount_overhead;
	int nullfunc_loop_overhead;
	int nullfunc_loop_profiled_time;
	uintfptr_t tmp_addr;
#endif

	/*
	 * Round lowpc and highpc to multiples of the density we're using
	 * so the rest of the scaling (here and in gprof) stays in ints.
	 */
	p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER));
	p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER));
	p->textsize = p->highpc - p->lowpc;
	kprintf("Profiling kernel, textsize=%lu [%x..%x]\n",
	       p->textsize, p->lowpc, p->highpc);
	p->kcountsize = p->textsize / HISTFRACTION;
	p->hashfraction = HASHFRACTION;
	p->fromssize = p->textsize / HASHFRACTION;
	p->tolimit = p->textsize * ARCDENSITY / 100;
	if (p->tolimit < MINARCS)
		p->tolimit = MINARCS;
	else if (p->tolimit > MAXARCS)
		p->tolimit = MAXARCS;
	p->tossize = p->tolimit * sizeof(struct tostruct);
	cp = (char *)kmalloc(p->kcountsize + p->fromssize + p->tossize,
	    M_GPROF, M_NOWAIT | M_ZERO);
	if (cp == 0) {
		kprintf("No memory for profiling.\n");
		return;
	}
	p->tos = (struct tostruct *)cp;
	cp += p->tossize;
	p->kcount = (HISTCOUNTER *)cp;
	cp += p->kcountsize;
	p->froms = (u_short *)cp;

#ifdef GUPROF
	/* Initialize pointers to overhead counters. */
	p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime));
	p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount));
	p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount));

	/*
	 * Disable interrupts to avoid interference while we calibrate
	 * things.
	 */
	cpu_disable_intr();

	/*
	 * Determine overheads.
	 * XXX this needs to be repeated for each useful timer/counter.
	 */
	cputime_overhead = 0;
	startguprof(p);
	for (i = 0; i < CALIB_SCALE; i++)
		cputime_overhead += cputime();

	empty_loop();
	startguprof(p);
	empty_loop();
	empty_loop_time = cputime();

	nullfunc_loop_profiled();

	/*
	 * Start profiling.  There won't be any normal function calls since
	 * interrupts are disabled, but we will call the profiling routines
	 * directly to determine their overheads.
	 */
	p->state = GMON_PROF_HIRES;

	startguprof(p);
	nullfunc_loop_profiled();

	startguprof(p);
	for (i = 0; i < CALIB_SCALE; i++)
#if defined(__i386__) && __GNUC__ >= 2
		__asm("pushl %0; call __mcount; popl %%ecx"
		      :
		      : "i" (profil)
		      : "ax", "bx", "cx", "dx", "memory");
#else
#error
#endif
	mcount_overhead = KCOUNT(p, PC_TO_I(p, profil));

	startguprof(p);
	for (i = 0; i < CALIB_SCALE; i++)
#if defined(__i386__) && __GNUC__ >= 2
		    __asm("call " __XSTRING(HIDENAME(mexitcount)) "; 1:"
			  : : : "ax", "bx", "cx", "dx", "memory");
	__asm("movl $1b,%0" : "=rm" (tmp_addr));
#else
#error
#endif
	mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr));

	p->state = GMON_PROF_OFF;
	stopguprof(p);

	cpu_enable_intr();

	nullfunc_loop_profiled_time = 0;
	for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled;
	     tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end;
	     tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER))
		nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr));
#define CALIB_DOSCALE(count)	(((count) + CALIB_SCALE / 3) / CALIB_SCALE)
#define	c2n(count, freq)	((int)((count) * 1000000000LL / freq))
	kprintf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n",
	       CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)),
	       CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)),
	       CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)),
	       CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)),
	       CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate)));
	cputime_overhead -= empty_loop_time;
	mcount_overhead -= empty_loop_time;
	mexitcount_overhead -= empty_loop_time;

	/*-
	 * Profiling overheads are determined by the times between the
	 * following events:
	 *	MC1: mcount() is called
	 *	MC2: cputime() (called from mcount()) latches the timer
	 *	MC3: mcount() completes
	 *	ME1: mexitcount() is called
	 *	ME2: cputime() (called from mexitcount()) latches the timer
	 *	ME3: mexitcount() completes.
	 * The times between the events vary slightly depending on instruction
	 * combination and cache misses, etc.  Attempt to determine the
	 * minimum times.  These can be subtracted from the profiling times
	 * without much risk of reducing the profiling times below what they
	 * would be when profiling is not configured.  Abbreviate:
	 *	ab = minimum time between MC1 and MC3
	 *	a  = minumum time between MC1 and MC2
	 *	b  = minimum time between MC2 and MC3
	 *	cd = minimum time between ME1 and ME3
	 *	c  = minimum time between ME1 and ME2
	 *	d  = minimum time between ME2 and ME3.
	 * These satisfy the relations:
	 *	ab            <= mcount_overhead		(just measured)
	 *	a + b         <= ab
	 *	        cd    <= mexitcount_overhead		(just measured)
	 *	        c + d <= cd
	 *	a         + d <= nullfunc_loop_profiled_time	(just measured)
	 *	a >= 0, b >= 0, c >= 0, d >= 0.
	 * Assume that ab and cd are equal to the minimums.
	 */
	p->cputime_overhead = CALIB_DOSCALE(cputime_overhead);
	p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead);
	p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead
					       - cputime_overhead);
	nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time;
	p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead
						     - nullfunc_loop_overhead)
						    / 4);
	p->mexitcount_pre_overhead = p->mexitcount_overhead
				     + p->cputime_overhead
				     - p->mexitcount_post_overhead;
	p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead)
				 - p->mexitcount_post_overhead;
	p->mcount_post_overhead = p->mcount_overhead
				  + p->cputime_overhead
				  - p->mcount_pre_overhead;
	kprintf(
"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n",
	       c2n(p->cputime_overhead, p->profrate),
	       c2n(p->mcount_overhead, p->profrate),
	       c2n(p->mcount_pre_overhead, p->profrate),
	       c2n(p->mcount_post_overhead, p->profrate),
	       c2n(p->cputime_overhead, p->profrate),
	       c2n(p->mexitcount_overhead, p->profrate),
	       c2n(p->mexitcount_pre_overhead, p->profrate),
	       c2n(p->mexitcount_post_overhead, p->profrate));
	kprintf(
"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n",
	       p->cputime_overhead, p->mcount_overhead,
	       p->mcount_pre_overhead, p->mcount_post_overhead,
	       p->cputime_overhead, p->mexitcount_overhead,
	       p->mexitcount_pre_overhead, p->mexitcount_post_overhead);
#endif /* GUPROF */
}

/*
 * Return kernel profiling information.
 */
static int
sysctl_kern_prof(SYSCTL_HANDLER_ARGS)
{
	int *name = (int *) arg1;
	u_int namelen = arg2;
	struct gmonparam *gp = &_gmonparam;
	int error;
	int state;

	/* all sysctl names at this level are terminal */
	if (namelen != 1)
		return (ENOTDIR);		/* overloaded */

	switch (name[0]) {
	case GPROF_STATE:
		state = gp->state;
		error = sysctl_handle_int(oidp, &state, 0, req);
		if (error)
			return (error);
		if (!req->newptr)
			return (0);
		lwkt_gettoken(&proc0.p_token);
		if (state == GMON_PROF_OFF) {
			gp->state = state;
			stopprofclock(&proc0);
			stopguprof(gp);
		} else if (state == GMON_PROF_ON) {
			gp->state = GMON_PROF_OFF;
			stopguprof(gp);
			gp->profrate = profhz;
			startprofclock(&proc0);
			gp->state = state;
#ifdef GUPROF
		} else if (state == GMON_PROF_HIRES) {
			gp->state = GMON_PROF_OFF;
			stopprofclock(&proc0);
			startguprof(gp);
			gp->state = state;
#endif
		} else if (state != gp->state) {
			error = EINVAL;
		}
		lwkt_reltoken(&proc0.p_token);
		return (error);
	case GPROF_COUNT:
		return (sysctl_handle_opaque(oidp, 
			gp->kcount, gp->kcountsize, req));
	case GPROF_FROMS:
		return (sysctl_handle_opaque(oidp, 
			gp->froms, gp->fromssize, req));
	case GPROF_TOS:
		return (sysctl_handle_opaque(oidp, 
			gp->tos, gp->tossize, req));
	case GPROF_GMONPARAM:
		return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req));
	default:
		return (EOPNOTSUPP);
	}
	/* NOTREACHED */
}

SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, "");
#endif /* GPROF */

/*
 * Profiling system call.
 *
 * The scale factor is a fixed point number with 16 bits of fraction, so that
 * 1.0 is represented as 0x10000.  A scale factor of 0 turns off profiling.
 *
 * MPALMOSTSAFE
 */
int
sys_profil(struct profil_args *uap)
{
	struct proc *p = curproc;
	struct uprof *upp;

	if (uap->scale > (1 << 16))
		return (EINVAL);
	get_mplock();
	if (uap->scale == 0) {
		stopprofclock(p);
	} else {
		upp = &p->p_prof;

		/* Block profile interrupts while changing state. */
		crit_enter();
		upp->pr_off = uap->offset;
		upp->pr_scale = uap->scale;
		upp->pr_base = uap->samples;
		upp->pr_size = uap->size;
		startprofclock(p);
		crit_exit();
	}
	rel_mplock();
	return (0);
}

/*
 * Scale is a fixed-point number with the binary point 16 bits
 * into the value, and is <= 1.0.  pc is at most 32 bits, so the
 * intermediate result is at most 48 bits.
 */
#define	PC_TO_INDEX(pc, prof) \
	((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
	    (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)

/*
 * Collect user-level profiling statistics; called on a profiling tick,
 * when a process is running in user-mode.  This routine may be called
 * from an interrupt context.  We try to update the user profiling buffers
 * cheaply with fuswintr() and suswintr().  If that fails, we revert to
 * an AST that will vector us to trap() with a context in which copyin
 * and copyout will work.  Trap will then call addupc_task().
 *
 * XXX fuswintr() and suswintr() never worked (always returnde -1), remove
 * them.  It's just a bad idea to try to do this from a hard interrupt.
 *
 * Note that we may (rarely) not get around to the AST soon enough, and
 * lose profile ticks when the next tick overwrites this one, but in this
 * case the system is overloaded and the profile is probably already
 * inaccurate.
 */
void
addupc_intr(struct proc *p, u_long pc, u_int ticks)
{
	struct uprof *prof;
	caddr_t addr;
	u_int i;

	if (ticks == 0)
		return;
	prof = &p->p_prof;
	if (pc < prof->pr_off ||
	    (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
		return;			/* out of range; ignore */

	addr = prof->pr_base + i;
	prof->pr_addr = pc;
	prof->pr_ticks = ticks;
	need_proftick();
}

/*
 * Much like before, but we can afford to take faults here.  If the
 * update fails, we simply turn off profiling.
 */
void
addupc_task(struct proc *p, u_long pc, u_int ticks)
{
	struct uprof *prof;
	caddr_t addr;
	u_int i;
	u_short v;

	/* Testing P_PROFIL may be unnecessary, but is certainly safe. */
	if ((p->p_flags & P_PROFIL) == 0 || ticks == 0)
		return;

	prof = &p->p_prof;
	if (pc < prof->pr_off ||
	    (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
		return;

	addr = prof->pr_base + i;
	if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) {
		v += ticks;
		if (copyout((caddr_t)&v, addr, sizeof(v)) == 0)
			return;
	}
	stopprofclock(p);
}
Commit	Line	Data
984263bc MD	1	/*-
	2	* Copyright (c) 1982, 1986, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	* 3. All advertising materials mentioning features or use of this software
	14	* must display the following acknowledgement:
	15	* This product includes software developed by the University of
	16	* California, Berkeley and its contributors.
	17	* 4. Neither the name of the University nor the names of its contributors
	18	* may be used to endorse or promote products derived from this software
	19	* without specific prior written permission.
	20	*
	21	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	22	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	23	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	24	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	25	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	26	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	27	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	28	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	29	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	30	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	31	* SUCH DAMAGE.
	32	*
	33	* @(#)subr_prof.c 8.3 (Berkeley) 9/23/93
	34	* $FreeBSD: src/sys/kern/subr_prof.c,v 1.32.2.2 2000/08/03 00:09:32 ps Exp $
	35	*/
	36
	37	#include <sys/param.h>
	38	#include <sys/systm.h>
	39	#include <sys/sysproto.h>
	40	#include <sys/kernel.h>
	41	#include <sys/proc.h>
	42	#include <sys/resourcevar.h>
	43	#include <sys/sysctl.h>
684a93c4	44
e43a034f	45	#include <sys/thread2.h>
684a93c4	46	#include <sys/mplock2.h>
984263bc	47
984263bc MD	48	#include <machine/cpu.h>
	49
	50	#ifdef GPROF
	51	#include <sys/malloc.h>
	52	#include <sys/gmon.h>
	53	#undef MCOUNT
	54
	55	static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");
	56
402ed7e1	57	static void kmstartup (void *);
984263bc MD	58	SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL)
	59
	60	struct gmonparam _gmonparam = { GMON_PROF_OFF };
	61
	62	#ifdef GUPROF
	63	#include <machine/asmacros.h>
	64
	65	void
c972a82f	66	nullfunc_loop_profiled(void)
984263bc MD	67	{
	68	int i;
	69
	70	for (i = 0; i < CALIB_SCALE; i++)
	71	nullfunc_profiled();
	72	}
	73
	74	#define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */
	75
	76	void
c972a82f	77	nullfunc_profiled(void)
984263bc MD	78	{
	79	}
	80	#endif /* GUPROF */
	81
	82	static void
493c516a	83	kmstartup(void *dummy)
984263bc MD	84	{
	85	char *cp;
	86	struct gmonparam *p = &_gmonparam;
	87	#ifdef GUPROF
	88	int cputime_overhead;
	89	int empty_loop_time;
	90	int i;
	91	int mcount_overhead;
	92	int mexitcount_overhead;
	93	int nullfunc_loop_overhead;
	94	int nullfunc_loop_profiled_time;
	95	uintfptr_t tmp_addr;
	96	#endif
	97
	98	/*
	99	* Round lowpc and highpc to multiples of the density we're using
	100	* so the rest of the scaling (here and in gprof) stays in ints.
	101	*/
	102	p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER));
	103	p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER));
	104	p->textsize = p->highpc - p->lowpc;
6ea70f76	105	kprintf("Profiling kernel, textsize=%lu [%x..%x]\n",
984263bc MD	106	p->textsize, p->lowpc, p->highpc);
	107	p->kcountsize = p->textsize / HISTFRACTION;
	108	p->hashfraction = HASHFRACTION;
	109	p->fromssize = p->textsize / HASHFRACTION;
	110	p->tolimit = p->textsize * ARCDENSITY / 100;
	111	if (p->tolimit < MINARCS)
	112	p->tolimit = MINARCS;
	113	else if (p->tolimit > MAXARCS)
	114	p->tolimit = MAXARCS;
	115	p->tossize = p->tolimit * sizeof(struct tostruct);
397c071c	116	cp = (char *)kmalloc(p->kcountsize + p->fromssize + p->tossize,
0c374e73	117	M_GPROF, M_NOWAIT \| M_ZERO);
984263bc	118	if (cp == 0) {
6ea70f76	119	kprintf("No memory for profiling.\n");
984263bc MD	120	return;
984263bc MD	121	}
984263bc MD	122	p->tos = (struct tostruct *)cp;
	123	cp += p->tossize;
	124	p->kcount = (HISTCOUNTER *)cp;
	125	cp += p->kcountsize;
	126	p->froms = (u_short *)cp;
	127
	128	#ifdef GUPROF
	129	/* Initialize pointers to overhead counters. */
	130	p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime));
	131	p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount));
	132	p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount));
	133
	134	/*
	135	* Disable interrupts to avoid interference while we calibrate
	136	* things.
	137	*/
eac48440	138	cpu_disable_intr();
984263bc MD	139
	140	/*
	141	* Determine overheads.
	142	* XXX this needs to be repeated for each useful timer/counter.
	143	*/
	144	cputime_overhead = 0;
	145	startguprof(p);
	146	for (i = 0; i < CALIB_SCALE; i++)
	147	cputime_overhead += cputime();
	148
	149	empty_loop();
	150	startguprof(p);
	151	empty_loop();
	152	empty_loop_time = cputime();
	153
	154	nullfunc_loop_profiled();
	155
	156	/*
	157	* Start profiling. There won't be any normal function calls since
	158	* interrupts are disabled, but we will call the profiling routines
	159	* directly to determine their overheads.
	160	*/
	161	p->state = GMON_PROF_HIRES;
	162
	163	startguprof(p);
	164	nullfunc_loop_profiled();
	165
	166	startguprof(p);
	167	for (i = 0; i < CALIB_SCALE; i++)
	168	#if defined(__i386__) && __GNUC__ >= 2
	169	__asm("pushl %0; call __mcount; popl %%ecx"
	170	:
	171	: "i" (profil)
	172	: "ax", "bx", "cx", "dx", "memory");
	173	#else
	174	#error
	175	#endif
	176	mcount_overhead = KCOUNT(p, PC_TO_I(p, profil));
	177
	178	startguprof(p);
	179	for (i = 0; i < CALIB_SCALE; i++)
	180	#if defined(__i386__) && __GNUC__ >= 2
	181	__asm("call " __XSTRING(HIDENAME(mexitcount)) "; 1:"
	182	: : : "ax", "bx", "cx", "dx", "memory");
	183	__asm("movl $1b,%0" : "=rm" (tmp_addr));
	184	#else
	185	#error
	186	#endif
	187	mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr));
	188
	189	p->state = GMON_PROF_OFF;
	190	stopguprof(p);
	191
eac48440	192	cpu_enable_intr();
984263bc MD	193
	194	nullfunc_loop_profiled_time = 0;
	195	for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled;
	196	tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end;
	197	tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER))
	198	nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr));
	199	#define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE)
	200	#define c2n(count, freq) ((int)((count) * 1000000000LL / freq))
6ea70f76	201	kprintf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n",
984263bc MD	202	CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)),
	203	CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)),
	204	CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)),
	205	CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)),
	206	CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate)));
	207	cputime_overhead -= empty_loop_time;
	208	mcount_overhead -= empty_loop_time;
	209	mexitcount_overhead -= empty_loop_time;
	210
	211	/*-
	212	* Profiling overheads are determined by the times between the
	213	* following events:
	214	* MC1: mcount() is called
	215	* MC2: cputime() (called from mcount()) latches the timer
	216	* MC3: mcount() completes
	217	* ME1: mexitcount() is called
	218	* ME2: cputime() (called from mexitcount()) latches the timer
	219	* ME3: mexitcount() completes.
	220	* The times between the events vary slightly depending on instruction
	221	* combination and cache misses, etc. Attempt to determine the
	222	* minimum times. These can be subtracted from the profiling times
	223	* without much risk of reducing the profiling times below what they
	224	* would be when profiling is not configured. Abbreviate:
	225	* ab = minimum time between MC1 and MC3
	226	* a = minumum time between MC1 and MC2
	227	* b = minimum time between MC2 and MC3
	228	* cd = minimum time between ME1 and ME3
	229	* c = minimum time between ME1 and ME2
	230	* d = minimum time between ME2 and ME3.
	231	* These satisfy the relations:
	232	* ab <= mcount_overhead (just measured)
	233	* a + b <= ab
	234	* cd <= mexitcount_overhead (just measured)
	235	* c + d <= cd
	236	* a + d <= nullfunc_loop_profiled_time (just measured)
	237	* a >= 0, b >= 0, c >= 0, d >= 0.
	238	* Assume that ab and cd are equal to the minimums.
	239	*/
	240	p->cputime_overhead = CALIB_DOSCALE(cputime_overhead);
	241	p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead);
	242	p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead
	243	- cputime_overhead);
	244	nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time;
	245	p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead
	246	- nullfunc_loop_overhead)
	247	/ 4);
	248	p->mexitcount_pre_overhead = p->mexitcount_overhead
	249	+ p->cputime_overhead
	250	- p->mexitcount_post_overhead;
	251	p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead)
	252	- p->mexitcount_post_overhead;
	253	p->mcount_post_overhead = p->mcount_overhead
	254	+ p->cputime_overhead
	255	- p->mcount_pre_overhead;
6ea70f76	256	kprintf(
984263bc MD	257	"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n",
	258	c2n(p->cputime_overhead, p->profrate),
	259	c2n(p->mcount_overhead, p->profrate),
	260	c2n(p->mcount_pre_overhead, p->profrate),
	261	c2n(p->mcount_post_overhead, p->profrate),
	262	c2n(p->cputime_overhead, p->profrate),
	263	c2n(p->mexitcount_overhead, p->profrate),
	264	c2n(p->mexitcount_pre_overhead, p->profrate),
	265	c2n(p->mexitcount_post_overhead, p->profrate));
6ea70f76	266	kprintf(
984263bc MD	267	"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n",
	268	p->cputime_overhead, p->mcount_overhead,
	269	p->mcount_pre_overhead, p->mcount_post_overhead,
	270	p->cputime_overhead, p->mexitcount_overhead,
	271	p->mexitcount_pre_overhead, p->mexitcount_post_overhead);
	272	#endif /* GUPROF */
	273	}
	274
	275	/*
	276	* Return kernel profiling information.
	277	*/
	278	static int
	279	sysctl_kern_prof(SYSCTL_HANDLER_ARGS)
	280	{
	281	int name = (int ) arg1;
	282	u_int namelen = arg2;
	283	struct gmonparam *gp = &_gmonparam;
	284	int error;
	285	int state;
	286
	287	/* all sysctl names at this level are terminal */
	288	if (namelen != 1)
	289	return (ENOTDIR); /* overloaded */
	290
	291	switch (name[0]) {
	292	case GPROF_STATE:
	293	state = gp->state;
	294	error = sysctl_handle_int(oidp, &state, 0, req);
	295	if (error)
	296	return (error);
	297	if (!req->newptr)
	298	return (0);
616516c8	299	lwkt_gettoken(&proc0.p_token);
984263bc MD	300	if (state == GMON_PROF_OFF) {
	301	gp->state = state;
	302	stopprofclock(&proc0);
	303	stopguprof(gp);
	304	} else if (state == GMON_PROF_ON) {
	305	gp->state = GMON_PROF_OFF;
	306	stopguprof(gp);
	307	gp->profrate = profhz;
	308	startprofclock(&proc0);
	309	gp->state = state;
	310	#ifdef GUPROF
	311	} else if (state == GMON_PROF_HIRES) {
	312	gp->state = GMON_PROF_OFF;
	313	stopprofclock(&proc0);
	314	startguprof(gp);
	315	gp->state = state;
	316	#endif
616516c8 MD	317	} else if (state != gp->state) {
	318	error = EINVAL;
	319	}
	320	lwkt_reltoken(&proc0.p_token);
	321	return (error);
984263bc MD	322	case GPROF_COUNT:
	323	return (sysctl_handle_opaque(oidp,
	324	gp->kcount, gp->kcountsize, req));
	325	case GPROF_FROMS:
	326	return (sysctl_handle_opaque(oidp,
	327	gp->froms, gp->fromssize, req));
	328	case GPROF_TOS:
	329	return (sysctl_handle_opaque(oidp,
	330	gp->tos, gp->tossize, req));
	331	case GPROF_GMONPARAM:
	332	return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req));
	333	default:
	334	return (EOPNOTSUPP);
	335	}
	336	/* NOTREACHED */
	337	}
	338
	339	SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, "");
	340	#endif /* GPROF */
	341
	342	/*
	343	* Profiling system call.
	344	*
	345	* The scale factor is a fixed point number with 16 bits of fraction, so that
	346	* 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
3919ced0 MD	347	*
3919ced0 MD	348	* MPALMOSTSAFE
984263bc	349	*/
984263bc	350	int
753fd850	351	sys_profil(struct profil_args *uap)
984263bc	352	{
41c20dac MD	353	struct proc *p = curproc;
41c20dac MD	354	struct uprof *upp;
984263bc MD	355
	356	if (uap->scale > (1 << 16))
	357	return (EINVAL);
3919ced0	358	get_mplock();
984263bc MD	359	if (uap->scale == 0) {
984263bc MD	360	stopprofclock(p);
3919ced0 MD	361	} else {
	362	upp = &p->p_prof;
	363
	364	/* Block profile interrupts while changing state. */
	365	crit_enter();
	366	upp->pr_off = uap->offset;
	367	upp->pr_scale = uap->scale;
	368	upp->pr_base = uap->samples;
	369	upp->pr_size = uap->size;
	370	startprofclock(p);
	371	crit_exit();
984263bc	372	}
3919ced0	373	rel_mplock();
984263bc MD	374	return (0);
	375	}
	376
	377	/*
	378	* Scale is a fixed-point number with the binary point 16 bits
	379	* into the value, and is <= 1.0. pc is at most 32 bits, so the
	380	* intermediate result is at most 48 bits.
	381	*/
	382	#define PC_TO_INDEX(pc, prof) \
	383	((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
	384	(u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
	385
	386	/*
	387	* Collect user-level profiling statistics; called on a profiling tick,
	388	* when a process is running in user-mode. This routine may be called
	389	* from an interrupt context. We try to update the user profiling buffers
	390	* cheaply with fuswintr() and suswintr(). If that fails, we revert to
	391	* an AST that will vector us to trap() with a context in which copyin
	392	* and copyout will work. Trap will then call addupc_task().
	393	*
9b662cfd MD	394	* XXX fuswintr() and suswintr() never worked (always returnde -1), remove
	395	* them. It's just a bad idea to try to do this from a hard interrupt.
	396	*
984263bc MD	397	* Note that we may (rarely) not get around to the AST soon enough, and
	398	* lose profile ticks when the next tick overwrites this one, but in this
	399	* case the system is overloaded and the profile is probably already
	400	* inaccurate.
	401	*/
	402	void
493c516a	403	addupc_intr(struct proc *p, u_long pc, u_int ticks)
984263bc	404	{
1fd87d54 RG	405	struct uprof *prof;
	406	caddr_t addr;
	407	u_int i;
984263bc MD	408
	409	if (ticks == 0)
	410	return;
93328593	411	prof = &p->p_prof;
984263bc MD	412	if (pc < prof->pr_off \|\|
	413	(i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
	414	return; /* out of range; ignore */
	415
	416	addr = prof->pr_base + i;
9b662cfd MD	417	prof->pr_addr = pc;
	418	prof->pr_ticks = ticks;
	419	need_proftick();
984263bc MD	420	}
	421
	422	/*
	423	* Much like before, but we can afford to take faults here. If the
	424	* update fails, we simply turn off profiling.
	425	*/
	426	void
493c516a	427	addupc_task(struct proc *p, u_long pc, u_int ticks)
984263bc	428	{
1fd87d54 RG	429	struct uprof *prof;
	430	caddr_t addr;
	431	u_int i;
984263bc MD	432	u_short v;
	433
	434	/* Testing P_PROFIL may be unnecessary, but is certainly safe. */
4643740a	435	if ((p->p_flags & P_PROFIL) == 0 \|\| ticks == 0)
984263bc MD	436	return;
984263bc MD	437
93328593	438	prof = &p->p_prof;
984263bc MD	439	if (pc < prof->pr_off \|\|
	440	(i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
	441	return;
	442
	443	addr = prof->pr_base + i;
	444	if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) {
	445	v += ticks;
	446	if (copyout((caddr_t)&v, addr, sizeof(v)) == 0)
	447	return;
	448	}
	449	stopprofclock(p);
	450	}