PERFORCE change 98625 for review

[John Birrell]

http://perforce.freebsd.org/chv.cgi?CH=98625

Change 98625 by jb at jb_freebsd2 on 2006/06/06 03:08:18

	Add a function to get DTrace high resolution time independent of any
	other functions that can have DTrace probes enabled on them.
	
	DTrace high resolution time is equivalent to FreeBSD's nanouptime.

Affected files ...

.. //depot/projects/dtrace/src/sys/contrib/opensolaris/uts/common/sys/dtrace.h#18 edit
.. //depot/projects/dtrace/src/sys/kern/kern_tc.c#2 edit
.. //depot/projects/dtrace/src/sys/sys/time.h#4 edit

Differences ...

==== //depot/projects/dtrace/src/sys/contrib/opensolaris/uts/common/sys/dtrace.h#18 (text) ====

@@ -2231,7 +2231,9 @@
 extern void (*dtrace_debugger_fini)(void);
 extern dtrace_cacheid_t dtrace_predcache_id;
 
+#if defined(sun)
 extern hrtime_t dtrace_gethrtime(void);
+#endif
 extern void dtrace_sync(void);
 extern void dtrace_toxic_ranges(void (*)(uintptr_t, uintptr_t));
 extern void dtrace_xcall(processorid_t, dtrace_xcall_t, void *);

==== //depot/projects/dtrace/src/sys/kern/kern_tc.c#2 (text+ko) ====

@@ -10,6 +10,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD: src/sys/kern/kern_tc.c,v 1.175 2006/03/15 20:22:32 phk Exp $");
 
+#include "opt_kdtrace.h"
 #include "opt_ntp.h"
 
 #include <sys/param.h>
@@ -303,6 +304,34 @@
 }
 
 /*
+ * DTrace needs a high resolution time function which can
+ * be called from a probe context and guaranteed not to have
+ * instrumented with probes itself. It avoids instrumenting
+ * functions with the 'dtrace_' prefix.
+ *
+ * The 'high resolution' time is actually nanoseconds uptime.
+ */
+#ifdef KDTRACE
+uint64_t
+dtrace_gethrtime()
+{
+	struct timehands *th;
+	u_int gen;
+	uint64_t hrt;
+
+	do {
+		th = timehands;
+		gen = th->th_generation;
+
+		hrt = th->th_offset.sec * (uint64_t)1000000000 +
+		    (((uint64_t)1000000000 * (uint32_t)(th->th_offset.frac >> 32)) >> 32);
+	} while (gen == 0 || gen != th->th_generation);
+
+	return (hrt);
+}
+#endif
+
+/*
  * Initialize a new timecounter and possibly use it.
  */
 void

==== //depot/projects/dtrace/src/sys/sys/time.h#4 (text+ko) ====

@@ -304,6 +304,7 @@
 void	timevaladd(struct timeval *t1, const struct timeval *t2);
 void	timevalsub(struct timeval *t1, const struct timeval *t2);
 int	tvtohz(struct timeval *tv);
+uint64_t	dtrace_gethrtime(void);
 #else /* !_KERNEL */
 #include <time.h>