Implemented non-statistical kernel profiling. This is based on

looking at a high resolution clock for each of the following events:
function call, function return, interrupt entry, interrupt exit,
and interesting branches.  The differences between the times of
these events are added at appropriate places in a ordinary histogram
(as if very fast statistical profiling sampled the pc at those
places) so that ordinary gprof can be used to analyze the times.

gmon.h:
Histogram counters need to be 4 bytes for microsecond resolutions.
They will need to be larger for the 586 clock.
The comments were vax-centric and wrong even on vaxes.  Does anyone
disagree?

gprof4.c:
The standard gprof should support counters of all integral sizes
and the size of the counter should be in the gmon header.  This
hack will do until then.  (Use gprof4 -u to examine the results
of non-statistical profiling.)

config/*:
Non-statistical profiling is configured with `config -pp'.
`config -p' still gives ordinary profiling.

kgmon/*:
Non-statistical profiling is enabled with `kgmon -B'.  `kgmon -b'
still enables ordinary profiling (and distables non-statistical
profiling) if non-statistical profiling is configured.

1 files changed, 3 insertions, 179 deletions

diff --git a/sys/libkern/mcount.c b/sys/libkern/mcount.c
index fc3625b..ed0e68d 100644
--- a/sys/libkern/mcount.c
+++ b/sys/libkern/mcount.c
@@ -1,180 +1,4 @@
-/*-
- * Copyright (c) 1983, 1992, 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.
- *
- * $Id: mcount.c,v 1.3 1994/09/15 15:41:48 paul Exp $
- */
+#define	GPROF4	1		/* XXX can't get at kernel options */
+#define	GUPROF	1		/* XXX can't get at kernel options */
 
-#include <sys/param.h>
-#include <sys/gmon.h>
-#ifdef KERNEL
-#include <i386/include/cpufunc.h>
-#endif
-
-/*
- * mcount is called on entry to each function compiled with the profiling
- * switch set.  _mcount(), which is declared in a machine-dependent way
- * with _MCOUNT_DECL, does the actual work and is either inlined into a
- * C routine or called by an assembly stub.  In any case, this magic is
- * taken care of by the MCOUNT definition in <machine/profile.h>.
- *
- * _mcount updates data structures that represent traversals of the
- * program's call graph edges.  frompc and selfpc are the return
- * address and function address that represents the given call graph edge.
- *
- * Note: the original BSD code used the same variable (frompcindex) for
- * both frompcindex and frompc.  Any reasonable, modern compiler will
- * perform this optimization.
- */
-_MCOUNT_DECL(frompc, selfpc)	/* _mcount; may be static, inline, etc */
-	register u_long frompc, selfpc;
-{
-	register u_short *frompcindex;
-	register struct tostruct *top, *prevtop;
-	register struct gmonparam *p;
-	register long toindex;
-#ifdef KERNEL
-	register int s;
-	u_long save_eflags;
-#endif
-
-	p = &_gmonparam;
-	/*
-	 * check that we are profiling
-	 * and that we aren't recursively invoked.
-	 */
-	if (p->state != GMON_PROF_ON)
-		return;
-#ifdef KERNEL
-	MCOUNT_ENTER;
-#else
-	p->state = GMON_PROF_BUSY;
-#endif
-	/*
-	 * check that frompcindex is a reasonable pc value.
-	 * for example:	signal catchers get called from the stack,
-	 *		not from text space.  too bad.
-	 */
-	frompc -= p->lowpc;
-	if (frompc > p->textsize)
-		goto done;
-
-	frompcindex = &p->froms[frompc / (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;
-#else
-	p->state = GMON_PROF_ON;
-#endif
-	return;
-overflow:
-	p->state = GMON_PROF_ERROR;
-#ifdef KERNEL
-	MCOUNT_EXIT;
-#endif
-	return;
-}
-
-/*
- * Actual definition of mcount function.  Defined in <machine/profile.h>,
- * which is included by <sys/gmon.h>.
- */
-MCOUNT
+#include "../lib/libc/gmon/mcount.c"	/* XXX */