Esempio n. 1
0
/* _mcount; may be static, inline, etc */
_MCOUNT_DECL(uintfptr_t frompc, uintfptr_t selfpc)
{
#ifdef GUPROF
    int delta;
#endif
    fptrdiff_t frompci;
    u_short *frompcindex;
    struct tostruct *top, *prevtop;
    struct gmonparam *p;
    long toindex;
#if defined(_KERNEL) && !defined(_KERNEL_VIRTUAL)
    MCOUNT_DECL(s)
#endif

    p = &_gmonparam;
#ifndef GUPROF			/* XXX */
    /*
     * check that we are profiling
     * and that we aren't recursively invoked.
     */
    if (p->state != GMON_PROF_ON)
        return;
#endif
#if defined(_KERNEL) && !defined(_KERNEL_VIRTUAL)
    MCOUNT_ENTER(s);
#else
    p->state = GMON_PROF_BUSY;
#endif
    frompci = frompc - p->lowpc;

#if defined(_KERNEL) && !defined(_KERNEL_VIRTUAL)
    /*
     * When we are called from an exception handler, frompci may be
     * for a user address.  Convert such frompci's to the index of
     * user() to merge all user counts.
     *
     * XXX doesn't work properly with vkernel
     */
    if (frompci >= p->textsize) {
        if (frompci + p->lowpc
                >= (uintfptr_t)(VM_MAX_USER_ADDRESS + UPAGES * PAGE_SIZE))
            goto done;
        frompci = (uintfptr_t)user - p->lowpc;
        if (frompci >= p->textsize)
            goto done;
    }
#endif

#ifdef GUPROF
    if (p->state == GMON_PROF_HIRES) {
        /*
         * Count the time since cputime() was previously called
         * against `frompc'.  Compensate for overheads.
         *
         * cputime() sets its prev_count variable to the count when
         * it is called.  This in effect starts a counter for
         * the next period of execution (normally from now until
         * the next call to mcount() or mexitcount()).  We set
         * cputime_bias to compensate for our own overhead.
         *
         * We use the usual sampling counters since they can be
         * located efficiently.  4-byte counters are usually
         * necessary.  gprof will add up the scattered counts
         * just like it does for statistical profiling.  All
         * counts are signed so that underflow in the subtractions
         * doesn't matter much (negative counts are normally
         * compensated for by larger counts elsewhere).  Underflow
         * shouldn't occur, but may be caused by slightly wrong
         * calibrations or from not clearing cputime_bias.
         */
        delta = cputime() - cputime_bias - p->mcount_pre_overhead;
        cputime_bias = p->mcount_post_overhead;
        KCOUNT(p, frompci) += delta;
        *p->cputime_count += p->cputime_overhead;
        *p->mcount_count += p->mcount_overhead;
    }
#endif /* GUPROF */

#if defined(_KERNEL) && !defined(_KERNEL_VIRTUAL)
    /*
     * When we are called from an exception handler, frompc is faked
     * to be for where the exception occurred.  We've just solidified
     * the count for there.  Now convert frompci to the index of btrap()
     * for trap handlers and bintr() for interrupt handlers to make
     * exceptions appear in the call graph as calls from btrap() and
     * bintr() instead of calls from all over.
     */
    if ((uintfptr_t)selfpc >= (uintfptr_t)btrap
            && (uintfptr_t)selfpc < (uintfptr_t)eintr) {
        if ((uintfptr_t)selfpc >= (uintfptr_t)bintr)
            frompci = (uintfptr_t)bintr - p->lowpc;
        else
            frompci = (uintfptr_t)btrap - p->lowpc;
    }
#endif

    /*
     * check that frompc is a reasonable pc value.
     * for example:	signal catchers get called from the stack,
     *		not from text space.  too bad.
     */
    if (frompci >= p->textsize)
        goto done;

    frompcindex = &p->froms[frompci / (p->hashfraction * sizeof(*p->froms))];
    toindex = *frompcindex;
    if (toindex == 0) {
        /*
         *	first time traversing this arc
         */
        toindex = ++p->tos[0].link;
        if (toindex >= p->tolimit)
            /* halt further profiling */
            goto overflow;

        *frompcindex = toindex;
        top = &p->tos[toindex];
        top->selfpc = selfpc;
        top->count = 1;
        top->link = 0;
        goto done;
    }
    top = &p->tos[toindex];
    if (top->selfpc == selfpc) {
        /*
         * arc at front of chain; usual case.
         */
        top->count++;
        goto done;
    }
    /*
     * have to go looking down chain for it.
     * top points to what we are looking at,
     * prevtop points to previous top.
     * we know it is not at the head of the chain.
     */
    for (; /* goto done */; ) {
        if (top->link == 0) {
            /*
             * top is end of the chain and none of the chain
             * had top->selfpc == selfpc.
             * so we allocate a new tostruct
             * and link it to the head of the chain.
             */
            toindex = ++p->tos[0].link;
            if (toindex >= p->tolimit)
                goto overflow;

            top = &p->tos[toindex];
            top->selfpc = selfpc;
            top->count = 1;
            top->link = *frompcindex;
            *frompcindex = toindex;
            goto done;
        }
        /*
         * otherwise, check the next arc on the chain.
         */
        prevtop = top;
        top = &p->tos[top->link];
        if (top->selfpc == selfpc) {
            /*
             * there it is.
             * increment its count
             * move it to the head of the chain.
             */
            top->count++;
            toindex = prevtop->link;
            prevtop->link = top->link;
            top->link = *frompcindex;
            *frompcindex = toindex;
            goto done;
        }

    }
done:
#if defined(_KERNEL) && !defined(_KERNEL_VIRTUAL)
    MCOUNT_EXIT(s);
#else
    p->state = GMON_PROF_ON;
#endif
    return;
overflow:
    p->state = GMON_PROF_ERROR;
#if defined(_KERNEL) && !defined(_KERNEL_VIRTUAL)
    MCOUNT_EXIT(s);
#endif
    return;
}
Esempio n. 2
0
/* _mcount; may be static, inline, etc */
_MCOUNT_DECL(uintfptr_t frompc, uintfptr_t selfpc)
{
#ifdef GUPROF
	u_int delta;
#endif
	fptrdiff_t frompci;
	u_short *frompcindex;
	struct tostruct *top, *prevtop;
	struct gmonparam *p;
	long toindex;
#ifdef _KERNEL
	MCOUNT_DECL(s)
#endif

	p = &_gmonparam;
#ifndef GUPROF			/* XXX */
	/*
	 * check that we are profiling
	 * and that we aren't recursively invoked.
	 */
	if (p->state != GMON_PROF_ON)
		return;
#endif
#ifdef _KERNEL
	MCOUNT_ENTER(s);
#else
	if (!atomic_cmpset_acq_int(&p->state, GMON_PROF_ON, GMON_PROF_BUSY))
		return;
#endif
	frompci = frompc - p->lowpc;

#ifdef _KERNEL
	/*
	 * When we are called from an exception handler, frompci may be
	 * for a user address.  Convert such frompci's to the index of
	 * user() to merge all user counts.
	 */
	if (frompci >= p->textsize) {
		if (frompci + p->lowpc
		    >= (uintfptr_t)(VM_MAXUSER_ADDRESS + UPAGES * PAGE_SIZE))
			goto done;
		frompci = (uintfptr_t)user - p->lowpc;
		if (frompci >= p->textsize)
		    goto done;
	}
#endif

#ifdef GUPROF
	if (p->state != GMON_PROF_HIRES)
		goto skip_guprof_stuff;
	/*
	 * Look at the clock and add the count of clock cycles since the
	 * clock was last looked at to a counter for frompc.  This
	 * solidifies the count for the function containing frompc and
	 * effectively starts another clock for the current function.
	 * The count for the new clock will be solidified when another
	 * function call is made or the function returns.
	 *
	 * We use the usual sampling counters since they can be located
	 * efficiently.  4-byte counters are usually necessary.
	 *
	 * There are many complications for subtracting the profiling
	 * overheads from the counts for normal functions and adding
	 * them to the counts for mcount(), mexitcount() and cputime().
	 * We attempt to handle fractional cycles, but the overheads
	 * are usually underestimated because they are calibrated for
	 * a simpler than usual setup.
	 */
	delta = cputime() - p->mcount_overhead;
	p->cputime_overhead_resid += p->cputime_overhead_frac;
	p->mcount_overhead_resid += p->mcount_overhead_frac;
	if ((int)delta < 0)
		*p->mcount_count += delta + p->mcount_overhead
				    - p->cputime_overhead;
	else if (delta != 0) {
		if (p->cputime_overhead_resid >= CALIB_SCALE) {
			p->cputime_overhead_resid -= CALIB_SCALE;
			++*p->cputime_count;
			--delta;
		}
		if (delta != 0) {
			if (p->mcount_overhead_resid >= CALIB_SCALE) {
				p->mcount_overhead_resid -= CALIB_SCALE;
				++*p->mcount_count;
				--delta;
			}
			KCOUNT(p, frompci) += delta;
		}
		*p->mcount_count += p->mcount_overhead_sub;
	}
	*p->cputime_count += p->cputime_overhead;
skip_guprof_stuff:
#endif /* GUPROF */

#ifdef _KERNEL
	/*
	 * When we are called from an exception handler, frompc is faked
	 * to be for where the exception occurred.  We've just solidified
	 * the count for there.  Now convert frompci to the index of btrap()
	 * for trap handlers and bintr() for interrupt handlers to make
	 * exceptions appear in the call graph as calls from btrap() and
	 * bintr() instead of calls from all over.
	 */
	if ((uintfptr_t)selfpc >= (uintfptr_t)btrap
	    && (uintfptr_t)selfpc < (uintfptr_t)eintr) {
		if ((uintfptr_t)selfpc >= (uintfptr_t)bintr)
			frompci = (uintfptr_t)bintr - p->lowpc;
		else
			frompci = (uintfptr_t)btrap - p->lowpc;
	}
#endif

	/*
	 * check that frompc is a reasonable pc value.
	 * for example:	signal catchers get called from the stack,
	 *		not from text space.  too bad.
	 */
	if (frompci >= p->textsize)
		goto done;

	frompcindex = &p->froms[frompci / (p->hashfraction * sizeof(*p->froms))];
	toindex = *frompcindex;
	if (toindex == 0) {
		/*
		 *	first time traversing this arc
		 */
		toindex = ++p->tos[0].link;
		if (toindex >= p->tolimit)
			/* halt further profiling */
			goto overflow;

		*frompcindex = toindex;
		top = &p->tos[toindex];
		top->selfpc = selfpc;
		top->count = 1;
		top->link = 0;
		goto done;
	}
	top = &p->tos[toindex];
	if (top->selfpc == selfpc) {
		/*
		 * arc at front of chain; usual case.
		 */
		top->count++;
		goto done;
	}
	/*
	 * have to go looking down chain for it.
	 * top points to what we are looking at,
	 * prevtop points to previous top.
	 * we know it is not at the head of the chain.
	 */
	for (; /* goto done */; ) {
		if (top->link == 0) {
			/*
			 * top is end of the chain and none of the chain
			 * had top->selfpc == selfpc.
			 * so we allocate a new tostruct
			 * and link it to the head of the chain.
			 */
			toindex = ++p->tos[0].link;
			if (toindex >= p->tolimit)
				goto overflow;

			top = &p->tos[toindex];
			top->selfpc = selfpc;
			top->count = 1;
			top->link = *frompcindex;
			*frompcindex = toindex;
			goto done;
		}
		/*
		 * otherwise, check the next arc on the chain.
		 */
		prevtop = top;
		top = &p->tos[top->link];
		if (top->selfpc == selfpc) {
			/*
			 * there it is.
			 * increment its count
			 * move it to the head of the chain.
			 */
			top->count++;
			toindex = prevtop->link;
			prevtop->link = top->link;
			top->link = *frompcindex;
			*frompcindex = toindex;
			goto done;
		}

	}
done:
#ifdef _KERNEL
	MCOUNT_EXIT(s);
#else
	atomic_store_rel_int(&p->state, GMON_PROF_ON);
#endif
	return;
overflow:
	atomic_store_rel_int(&p->state, GMON_PROF_ERROR);
#ifdef _KERNEL
	MCOUNT_EXIT(s);
#endif
	return;
}