File:  [DragonFly] / src / sys / kern / subr_prof.c
Revision 1.9: download - view: text, annotated - select for diffs
Tue Jun 1 22:19:30 2004 UTC (10 years, 3 months ago) by dillon
Branches: MAIN
CVS tags: HEAD, DragonFly_Stable, DragonFly_Snap29Sep2004, DragonFly_Snap13Sep2004, DragonFly_RELEASE_1_2_Slip, DragonFly_RELEASE_1_2, DragonFly_1_0_REL, DragonFly_1_0_RC1, DragonFly_1_0A_REL
ANSIfication.  No operational changes.

Submitted-by: Tim Wickberg <me@k9mach3.org>

    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:  * $DragonFly: src/sys/kern/subr_prof.c,v 1.9 2004/06/01 22:19:30 dillon Exp $
   36:  */
   37: 
   38: #include <sys/param.h>
   39: #include <sys/systm.h>
   40: #include <sys/sysproto.h>
   41: #include <sys/kernel.h>
   42: #include <sys/proc.h>
   43: #include <sys/resourcevar.h>
   44: #include <sys/sysctl.h>
   45: 
   46: #include <machine/ipl.h>
   47: #include <machine/cpu.h>
   48: 
   49: #ifdef GPROF
   50: #include <sys/malloc.h>
   51: #include <sys/gmon.h>
   52: #undef MCOUNT
   53: 
   54: static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");
   55: 
   56: static void kmstartup (void *);
   57: SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL)
   58: 
   59: struct gmonparam _gmonparam = { GMON_PROF_OFF };
   60: 
   61: #ifdef GUPROF
   62: #include <machine/asmacros.h>
   63: 
   64: void
   65: nullfunc_loop_profiled()
   66: {
   67: 	int i;
   68: 
   69: 	for (i = 0; i < CALIB_SCALE; i++)
   70: 		nullfunc_profiled();
   71: }
   72: 
   73: #define	nullfunc_loop_profiled_end	nullfunc_profiled	/* XXX */
   74: 
   75: void
   76: nullfunc_profiled()
   77: {
   78: }
   79: #endif /* GUPROF */
   80: 
   81: static void
   82: kmstartup(void *dummy)
   83: {
   84: 	char *cp;
   85: 	struct gmonparam *p = &_gmonparam;
   86: #ifdef GUPROF
   87: 	int cputime_overhead;
   88: 	int empty_loop_time;
   89: 	int i;
   90: 	int mcount_overhead;
   91: 	int mexitcount_overhead;
   92: 	int nullfunc_loop_overhead;
   93: 	int nullfunc_loop_profiled_time;
   94: 	uintfptr_t tmp_addr;
   95: #endif
   96: 
   97: 	/*
   98: 	 * Round lowpc and highpc to multiples of the density we're using
   99: 	 * so the rest of the scaling (here and in gprof) stays in ints.
  100: 	 */
  101: 	p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER));
  102: 	p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER));
  103: 	p->textsize = p->highpc - p->lowpc;
  104: 	printf("Profiling kernel, textsize=%lu [%x..%x]\n",
  105: 	       p->textsize, p->lowpc, p->highpc);
  106: 	p->kcountsize = p->textsize / HISTFRACTION;
  107: 	p->hashfraction = HASHFRACTION;
  108: 	p->fromssize = p->textsize / HASHFRACTION;
  109: 	p->tolimit = p->textsize * ARCDENSITY / 100;
  110: 	if (p->tolimit < MINARCS)
  111: 		p->tolimit = MINARCS;
  112: 	else if (p->tolimit > MAXARCS)
  113: 		p->tolimit = MAXARCS;
  114: 	p->tossize = p->tolimit * sizeof(struct tostruct);
  115: 	cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize,
  116: 	    M_GPROF, M_NOWAIT);
  117: 	if (cp == 0) {
  118: 		printf("No memory for profiling.\n");
  119: 		return;
  120: 	}
  121: 	bzero(cp, p->kcountsize + p->tossize + p->fromssize);
  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: 	 */
  138: 	cpu_disable_intr();
  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: 
  192: 	cpu_enable_intr();
  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))
  201: 	printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n",
  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;
  256: 	printf(
  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));
  266: 	printf(
  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);
  299: 		if (state == GMON_PROF_OFF) {
  300: 			gp->state = state;
  301: 			stopprofclock(&proc0);
  302: 			stopguprof(gp);
  303: 		} else if (state == GMON_PROF_ON) {
  304: 			gp->state = GMON_PROF_OFF;
  305: 			stopguprof(gp);
  306: 			gp->profrate = profhz;
  307: 			startprofclock(&proc0);
  308: 			gp->state = state;
  309: #ifdef GUPROF
  310: 		} else if (state == GMON_PROF_HIRES) {
  311: 			gp->state = GMON_PROF_OFF;
  312: 			stopprofclock(&proc0);
  313: 			startguprof(gp);
  314: 			gp->state = state;
  315: #endif
  316: 		} else if (state != gp->state)
  317: 			return (EINVAL);
  318: 		return (0);
  319: 	case GPROF_COUNT:
  320: 		return (sysctl_handle_opaque(oidp, 
  321: 			gp->kcount, gp->kcountsize, req));
  322: 	case GPROF_FROMS:
  323: 		return (sysctl_handle_opaque(oidp, 
  324: 			gp->froms, gp->fromssize, req));
  325: 	case GPROF_TOS:
  326: 		return (sysctl_handle_opaque(oidp, 
  327: 			gp->tos, gp->tossize, req));
  328: 	case GPROF_GMONPARAM:
  329: 		return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req));
  330: 	default:
  331: 		return (EOPNOTSUPP);
  332: 	}
  333: 	/* NOTREACHED */
  334: }
  335: 
  336: SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, "");
  337: #endif /* GPROF */
  338: 
  339: /*
  340:  * Profiling system call.
  341:  *
  342:  * The scale factor is a fixed point number with 16 bits of fraction, so that
  343:  * 1.0 is represented as 0x10000.  A scale factor of 0 turns off profiling.
  344:  */
  345: /* ARGSUSED */
  346: int
  347: profil(struct profil_args *uap)
  348: {
  349: 	struct proc *p = curproc;
  350: 	struct uprof *upp;
  351: 	int s;
  352: 
  353: 	if (uap->scale > (1 << 16))
  354: 		return (EINVAL);
  355: 	if (uap->scale == 0) {
  356: 		stopprofclock(p);
  357: 		return (0);
  358: 	}
  359: 	upp = &p->p_stats->p_prof;
  360: 
  361: 	/* Block profile interrupts while changing state. */
  362: 	s = splstatclock();
  363: 	upp->pr_off = uap->offset;
  364: 	upp->pr_scale = uap->scale;
  365: 	upp->pr_base = uap->samples;
  366: 	upp->pr_size = uap->size;
  367: 	startprofclock(p);
  368: 	splx(s);
  369: 
  370: 	return (0);
  371: }
  372: 
  373: /*
  374:  * Scale is a fixed-point number with the binary point 16 bits
  375:  * into the value, and is <= 1.0.  pc is at most 32 bits, so the
  376:  * intermediate result is at most 48 bits.
  377:  */
  378: #define	PC_TO_INDEX(pc, prof) \
  379: 	((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
  380: 	    (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
  381: 
  382: /*
  383:  * Collect user-level profiling statistics; called on a profiling tick,
  384:  * when a process is running in user-mode.  This routine may be called
  385:  * from an interrupt context.  We try to update the user profiling buffers
  386:  * cheaply with fuswintr() and suswintr().  If that fails, we revert to
  387:  * an AST that will vector us to trap() with a context in which copyin
  388:  * and copyout will work.  Trap will then call addupc_task().
  389:  *
  390:  * Note that we may (rarely) not get around to the AST soon enough, and
  391:  * lose profile ticks when the next tick overwrites this one, but in this
  392:  * case the system is overloaded and the profile is probably already
  393:  * inaccurate.
  394:  */
  395: void
  396: addupc_intr(struct proc *p, u_long pc, u_int ticks)
  397: {
  398: 	struct uprof *prof;
  399: 	caddr_t addr;
  400: 	u_int i;
  401: 	int v;
  402: 
  403: 	if (ticks == 0)
  404: 		return;
  405: 	prof = &p->p_stats->p_prof;
  406: 	if (pc < prof->pr_off ||
  407: 	    (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
  408: 		return;			/* out of range; ignore */
  409: 
  410: 	addr = prof->pr_base + i;
  411: 	if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) {
  412: 		prof->pr_addr = pc;
  413: 		prof->pr_ticks = ticks;
  414: 		need_proftick();
  415: 	}
  416: }
  417: 
  418: /*
  419:  * Much like before, but we can afford to take faults here.  If the
  420:  * update fails, we simply turn off profiling.
  421:  */
  422: void
  423: addupc_task(struct proc *p, u_long pc, u_int ticks)
  424: {
  425: 	struct uprof *prof;
  426: 	caddr_t addr;
  427: 	u_int i;
  428: 	u_short v;
  429: 
  430: 	/* Testing P_PROFIL may be unnecessary, but is certainly safe. */
  431: 	if ((p->p_flag & P_PROFIL) == 0 || ticks == 0)
  432: 		return;
  433: 
  434: 	prof = &p->p_stats->p_prof;
  435: 	if (pc < prof->pr_off ||
  436: 	    (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
  437: 		return;
  438: 
  439: 	addr = prof->pr_base + i;
  440: 	if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) {
  441: 		v += ticks;
  442: 		if (copyout((caddr_t)&v, addr, sizeof(v)) == 0)
  443: 			return;
  444: 	}
  445: 	stopprofclock(p);
  446: }