Improved non-statistical (GUPROF) profiling:

- use a more accurate and more efficient method of compensating for
  overheads.  The old method counted too much time against leaf
  functions.
- normally use the Pentium timestamp counter if available.
  On Pentiums, the times are now accurate to within a couple of cpu
  clock cycles per function call in the (unlikely) event that there
  are no cache misses in or caused by the profiling code.
- optionally use an arbitrary Pentium event counter if available.
- optionally regress to using the i8254 counter.
- scaled the i8254 counter by a factor of 128.  Now the i8254 counters
  overflow slightly faster than the TSC counters for a 150MHz Pentium :-)
  (after about 16 seconds).  This is to avoid fractional overheads.

files.i386:
permon.c temporarily has to be classified as a profiling-routine
because a couple of functions in it may be called from profiling code.

options.i386:
- I586_CTR_GUPROF is currently unused (oops).
- I586_PMC_GUPROF should be something like 0x70000 to enable (but not
  use unless prof_machdep.c is changed) support for Pentium event
  counters.  7 is a control mode and the counter number 0 is somewhere
  in the 0000 bits (see perfmon.h for the encoding).

profile.h:
- added declarations.
- cleaned up separation of user mode declarations.

prof_machdep.c:
Mostly clock-select changes.  The default clock can be changed by
editing kmem.  There should be a sysctl for this.

subr_prof.c:
- added copyright.
- calibrate overheads for the new method.
- documented new method.
- fixed races and and machine dependencies in start/stop code.

mcount.c:
Use the new overhead compensation method.

gmon.h:
- changed GPROF4 counter type from unsigned to int.  Oops, this should
  be machine-dependent and/or int32_t.
- reorganized overhead counters.

Submitted by:	Pentium event counter changes mostly by wollman

4 files changed, 190 insertions, 21 deletions

diff --git a/sys/i386/conf/files.i386 b/sys/i386/conf/files.i386
index 67afe44..06d34ff 100644
--- a/sys/i386/conf/files.i386
+++ b/sys/i386/conf/files.i386
@@ -1,7 +1,7 @@
 # This file tells config what files go into building a kernel,
 # files marked standard are always included.
 #
-#	$Id: files.i386,v 1.139 1996/08/27 19:45:54 pst Exp $
+#	$Id: files.i386,v 1.140 1996/09/11 19:53:30 phk Exp $
 #
 aic7xxx_asm			optional	ahc	device-driver	   \
 	dependency 	"$S/dev/aic7xxx/aic7xxx_asm.c"			   \
@@ -51,6 +51,7 @@ i386/i386/machdep.c		standard
 i386/i386/math_emulate.c	optional	math_emulate
 i386/i386/mem.c			standard
 i386/i386/microtime.s		standard
+i386/i386/perfmon.c		optional	perfmon	profiling-routine
 i386/i386/perfmon.c		optional	perfmon
 i386/i386/pmap.c		standard
 i386/i386/procfs_machdep.c	standard
diff --git a/sys/i386/conf/options.i386 b/sys/i386/conf/options.i386
index 3d3a3f700..7c09359 100644
--- a/sys/i386/conf/options.i386
+++ b/sys/i386/conf/options.i386
@@ -1,4 +1,4 @@
-#	$Id: options.i386,v 1.22 1996/10/09 18:36:44 bde Exp $
+#	$Id: options.i386,v 1.23 1996/10/09 19:47:07 bde Exp $
 BOUNCEPAGES		opt_bounce.h
 USER_LDT
 MATH_EMULATE		opt_math_emulate.h
@@ -18,6 +18,8 @@ COMCONSOLE		opt_comconsole.h
 COM_ESP			opt_sio.h
 COM_MULTIPORT		opt_sio.h
 DSI_SOFT_MODEM		opt_sio.h
+I586_CTR_GUPROF		opt_i586_guprof.h
+I586_PMC_GUPROF		opt_i586_guprof.h
 FAT_CURSOR		opt_pcvt.h
 PCVT_FREEBSD		opt_pcvt.h
 PCVT_SCANSET		opt_pcvt.h
diff --git a/sys/i386/include/profile.h b/sys/i386/include/profile.h
index 4b9d51b..08d0dbd 100644
--- a/sys/i386/include/profile.h
+++ b/sys/i386/include/profile.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)profile.h	8.1 (Berkeley) 6/11/93
- * $Id: profile.h,v 1.6 1996/01/01 17:11:21 bde Exp $
+ * $Id: profile.h,v 1.7 1996/08/28 20:15:25 bde Exp $
  */
 
 #ifndef _MACHINE_PROFILE_H_
@@ -97,18 +97,44 @@ typedef	u_int	fptrint_t;
  */
 typedef	int	fptrdiff_t;
 
-__BEGIN_DECLS
 #ifdef KERNEL
+
 void	mcount __P((fptrint_t frompc, fptrint_t selfpc));
+
+#ifdef GUPROF
+struct gmonparam;
+
+void	nullfunc_loop_profiled __P((void));
+void	nullfunc_profiled __P((void));
+void	startguprof __P((struct gmonparam *p));
+void	stopguprof __P((struct gmonparam *p));
 #else
+#define	startguprof(p)
+#define	stopguprof(p)
+#endif /* GUPROF */
+
+#else /* !KERNEL */
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
 void	mcount __P((void)) __asm("mcount");
 static void	_mcount __P((fptrint_t frompc, fptrint_t selfpc));
-#endif
+__END_DECLS
+
+#endif /* KERNEL */
 
 #ifdef GUPROF
-u_int	cputime __P((void));
+/* XXX doesn't quite work outside kernel yet. */
+extern int	cputime_bias;
+
+__BEGIN_DECLS
+int	cputime __P((void));
+void	empty_loop __P((void));
 void	mexitcount __P((fptrint_t selfpc));
-#endif
+void	nullfunc __P((void));
+void	nullfunc_loop __P((void));
 __END_DECLS
+#endif
 
 #endif /* !_MACHINE_PROFILE_H_ */
diff --git a/sys/i386/isa/prof_machdep.c b/sys/i386/isa/prof_machdep.c
index f140b84..62c8df5 100644
--- a/sys/i386/isa/prof_machdep.c
+++ b/sys/i386/isa/prof_machdep.c
@@ -1,17 +1,64 @@
-/*
- * NEED A COPYRIGHT NOPTICE HERE
+/*-
+ * Copyright (c) 1996 Bruce D. Evans.
+ * 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.
  *
- *	$Id$
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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: prof_machdep.c,v 1.2 1996/04/08 16:41:06 wollman Exp $
  */
+
+#ifdef GUPROF
+#include "opt_cpu.h"
+#include "opt_i586_guprof.h"
+#include "opt_perfmon.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/gmon.h>
+
 #include <machine/clock.h>
+#include <machine/perfmon.h>
+#include <machine/profile.h>
+#endif
+
 #include <i386/isa/isa.h>
 #include <i386/isa/timerreg.h>
 
 #ifdef GUPROF
-extern u_int	cputime __P((void));
+#define	CPUTIME_CLOCK_UNINITIALIZED	0
+#define	CPUTIME_CLOCK_I8254		1
+#define	CPUTIME_CLOCK_I586_CTR		2
+#define	CPUTIME_CLOCK_I586_PMC		3
+#define	CPUTIME_CLOCK_I8254_SHIFT	7
+
+int	cputime_bias = 1;	/* initialize for locality of reference */
+
+static int	cputime_clock = CPUTIME_CLOCK_UNINITIALIZED;
+#ifdef I586_PMC_GUPROF
+static u_int	cputime_clock_pmc_conf = I586_PMC_GUPROF;
+static int	cputime_clock_pmc_init;
+static struct gmonparam saved_gmp;
 #endif
+#endif /* GUPROF */
 
 #ifdef __GNUC__
 asm("
@@ -52,13 +99,13 @@ Lgot_frompc:
 	#
 	movl	(%esp),%eax
 
-	pushf
+	pushfl
 	pushl	%eax
 	pushl	%edx
 	cli
 	call	_mcount
 	addl	$8,%esp
-	popf
+	popfl
 Lmcount_exit:
 	ret
 ");
@@ -94,12 +141,12 @@ mexitcount:
 	pushl	%edx
 	pushl	%eax
 	movl	8(%esp),%eax
-	pushf
+	pushfl
 	pushl	%eax
 	cli
 	call	_mexitcount
 	addl	$4,%esp
-	popf
+	popfl
 	popl	%eax
 	popl	%edx
 Lmexitcount_exit:
@@ -113,20 +160,48 @@ Lmexitcount_exit:
  * Return the time elapsed since the last call.  The units are machine-
  * dependent.
  */
-u_int
+int
 cputime()
 {
 	u_int count;
-	u_int delta;
-	u_char low;
+	int delta;
+#ifdef I586_PMC_GUPROF
+	u_quad_t event_count;
+#endif
+	u_char high, low;
 	static u_int prev_count;
 
+#if defined(I586_CPU) || defined(I686_CPU)
+	if (cputime_clock == CPUTIME_CLOCK_I586_CTR) {
+		count = (u_int)rdtsc();
+		delta = (int)(count - prev_count);
+		prev_count = count;
+		return (delta);
+	}
+#ifdef I586_PMC_GUPROF
+	if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
+		/*
+		 * XXX permon_read() should be inlined so that the
+		 * perfmon module doesn't need to be compiled with
+		 * profiling disabled and so that it is fast.
+		 */
+		perfmon_read(0, &event_count);
+
+		count = (u_int)event_count;
+		delta = (int)(count - prev_count);
+		prev_count = count;
+		return (delta);
+	}
+#endif /* I586_PMC_GUPROF */
+#endif /* I586_CPU or I686_CPU */
+
 	/*
 	 * Read the current value of the 8254 timer counter 0.
 	 */
 	outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
 	low = inb(TIMER_CNTR0);
-	count = low | (inb(TIMER_CNTR0) << 8);
+	high = inb(TIMER_CNTR0);
+	count = ((high << 8) | low) << CPUTIME_CLOCK_I8254_SHIFT;
 
 	/*
 	 * The timer counts down from TIMER_CNTR0_MAX to 0 and then resets.
@@ -140,10 +215,75 @@ cputime()
 	delta = prev_count - count;
 	prev_count = count;
 	if ((int) delta <= 0)
-		return (delta + timer0_max_count);
+		return (delta + (timer0_max_count << CPUTIME_CLOCK_I8254_SHIFT));
 	return (delta);
 }
-#else /* not GUPROF */
+
+/*
+ * The start and stop routines need not be here since we turn off profiling
+ * before calling them.  They are here for convenience.
+ */
+
+void
+startguprof(gp)
+	struct gmonparam *gp;
+{
+	if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
+		cputime_clock = CPUTIME_CLOCK_I8254;
+#if defined(I586_CPU) || defined(I686_CPU)
+		if (i586_ctr_freq != 0)
+			cputime_clock = CPUTIME_CLOCK_I586_CTR;
+#endif
+	}
+	gp->profrate = timer_freq << CPUTIME_CLOCK_I8254_SHIFT;
+#if defined(I586_CPU) || defined(I686_CPU)
+	if (cputime_clock == CPUTIME_CLOCK_I586_CTR)
+		gp->profrate = i586_ctr_freq;
+#ifdef I586_PMC_GUPROF
+	else if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
+		if (perfmon_avail() &&
+		    perfmon_setup(0, cputime_clock_pmc_conf) == 0) {
+			if (perfmon_start(0) != 0)
+				perfmon_fini(0);
+			else {
+				/* XXX 1 event == 1 us. */
+				gp->profrate = 1000000;
+
+				saved_gmp = *gp;
+
+				/* Zap overheads.  They are invalid. */
+				gp->cputime_overhead = 0;
+				gp->mcount_overhead = 0;
+				gp->mcount_post_overhead = 0;
+				gp->mcount_pre_overhead = 0;
+				gp->mexitcount_overhead = 0;
+				gp->mexitcount_post_overhead = 0;
+				gp->mexitcount_pre_overhead = 0;
+
+				cputime_clock_pmc_init = TRUE;
+			}
+		}
+	}
+#endif /* I586_PMC_GUPROF */
+#endif /* I586_CPU or I686_CPU */
+	cputime_bias = 0;
+	cputime();
+}
+
+void
+stopguprof(gp)
+	struct gmonparam *gp;
+{
+#if defined(PERFMON) && defined(I586_PMC_GUPROF)
+	if (cputime_clock_pmc_init) {
+		*gp = saved_gmp;
+		perfmon_fini(0);
+		cputime_clock_pmc_init = FALSE;
+	}
+#endif
+}
+
+#else /* !GUPROF */
 #ifdef __GNUC__
 asm("
 	.text