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, 31 insertions, 5 deletions

diff --git a/sys/amd64/include/profile.h b/sys/amd64/include/profile.h
index 4b9d51b..08d0dbd 100644
--- a/sys/amd64/include/profile.h
+++ b/sys/amd64/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_ */