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

1 files changed, 10 insertions, 15 deletions

diff --git a/sys/sys/gmon.h b/sys/sys/gmon.h
index 619e94c45acb..6d5334c9669f 100644
--- a/sys/sys/gmon.h
+++ b/sys/sys/gmon.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)gmon.h	8.2 (Berkeley) 1/4/94
- * $Id: gmon.h,v 1.7 1995/08/29 03:09:14 bde Exp $
+ * $Id: gmon.h,v 1.8 1995/12/29 15:29:26 bde Exp $
  */
 
 #ifndef _SYS_GMON_H_
@@ -57,7 +57,7 @@ struct gmonhdr {
  * Type of histogram counters used in the kernel.
  */
 #ifdef GPROF4
-#define	HISTCOUNTER	unsigned
+#define	HISTCOUNTER	int
 #else
 #define	HISTCOUNTER	unsigned short
 #endif
@@ -174,22 +174,17 @@ struct gmonparam {
 	fptrint_t	highpc;
 	u_long		textsize;
 	u_long		hashfraction;
-	u_long		profrate;
+	int		profrate;	/* XXX wrong type to match gmonhdr */
 	HISTCOUNTER	*cputime_count;
-	u_int		cputime_overhead;
-	u_int		cputime_overhead_frac;
-	u_int		cputime_overhead_resid;
-	u_int		cputime_overhead_sub;
+	int		cputime_overhead;
 	HISTCOUNTER	*mcount_count;
-	u_int		mcount_overhead;
-	u_int		mcount_overhead_frac;
-	u_int		mcount_overhead_resid;
-	u_int		mcount_overhead_sub;
+	int		mcount_overhead;
+	int		mcount_post_overhead;
+	int		mcount_pre_overhead;
 	HISTCOUNTER	*mexitcount_count;
-	u_int		mexitcount_overhead;
-	u_int		mexitcount_overhead_frac;
-	u_int		mexitcount_overhead_resid;
-	u_int		mexitcount_overhead_sub;
+	int		mexitcount_overhead;
+	int		mexitcount_post_overhead;
+	int		mexitcount_pre_overhead;
 };
 extern struct gmonparam _gmonparam;