get_cyclecount(9) deprecation

[Jung-uk Kim]

Both get_cyclecount(9) and cpu_ticks() do almost exactly the same 
thing now assuming set_cputicker() is called with a correct function 
before get_cyclecount() is used, which is true for x86, at least.  
The only difference is get_cyclecount() may be inlined but I don't 
see much gain from the current uses.

Please review the patch.  Note I didn't really remove get_cyclecount() 
just because some random third-party module may use it as it is a 
documented feature while cpu_ticks is an internal KPI.

What do you think?

Jung-uk Kim
-------------- next part --------------
Index: sys/kern/kern_ktr.c
===================================================================
--- sys/kern/kern_ktr.c	(revision 219714)
+++ sys/kern/kern_ktr.c	(working copy)
@@ -73,7 +73,7 @@ __FBSDID("$FreeBSD$");
 #endif
 
 #ifndef KTR_TIME
-#define	KTR_TIME	get_cyclecount()
+#define	KTR_TIME	cpu_ticks()
 #endif
 
 #ifndef KTR_CPU
Index: sys/kern/init_main.c
===================================================================
--- sys/kern/init_main.c	(revision 219714)
+++ sys/kern/init_main.c	(working copy)
@@ -560,7 +560,7 @@ SYSINIT(p0init, SI_SUB_INTRINSIC, SI_ORDER_FIRST,
 static void
 proc0_post(void *dummy __unused)
 {
-	struct timespec ts;
+	struct bintime bt;
 	struct proc *p;
 	struct rusage ru;
 	struct thread *td;
@@ -590,8 +590,8 @@ proc0_post(void *dummy __unused)
 	/*
 	 * Give the ``random'' number generator a thump.
 	 */
-	nanotime(&ts);
-	srandom(ts.tv_sec ^ ts.tv_nsec);
+	bintime(&bt);
+	srandom(bt.sec ^ bt.frac);
 }
 SYSINIT(p0post, SI_SUB_INTRINSIC_POST, SI_ORDER_FIRST, proc0_post, NULL);
 
@@ -601,10 +601,10 @@ random_init(void *dummy __unused)
 
 	/*
 	 * After CPU has been started we have some randomness on most
-	 * platforms via get_cyclecount().  For platforms that don't
-	 * we will reseed random(9) in proc0_post() as well.
+	 * platforms via cpu_ticks().  For platforms that don't we will
+	 * reseed random(9) in proc0_post() as well.
 	 */
-	srandom(get_cyclecount());
+	srandom(cpu_ticks());
 }
 SYSINIT(random, SI_SUB_RANDOM, SI_ORDER_FIRST, random_init, NULL);
 
Index: sys/netinet/sctp_os_bsd.h
===================================================================
--- sys/netinet/sctp_os_bsd.h	(revision 219714)
+++ sys/netinet/sctp_os_bsd.h	(working copy)
@@ -129,7 +129,7 @@ MALLOC_DECLARE(SCTP_M_MCORE);
 
 #if defined(SCTP_LOCAL_TRACE_BUF)
 
-#define SCTP_GET_CYCLECOUNT get_cyclecount()
+#define SCTP_GET_CYCLECOUNT cpu_ticks()
 #define SCTP_CTR6 sctp_log_trace
 
 #else
Index: sys/dev/de/if_devar.h
===================================================================
--- sys/dev/de/if_devar.h	(revision 219714)
+++ sys/dev/de/if_devar.h	(working copy)
@@ -903,7 +903,7 @@ typedef u_long tulip_cycle_t;
 static __inline tulip_cycle_t
 TULIP_PERFREAD(void)
 {
-	return (get_cyclecount());
+	return (cpu_ticks());
 }
 
 #define	TULIP_PERFDIFF(s, f)	((f) - (s))
Index: sys/dev/random/randomdev_soft.c
===================================================================
--- sys/dev/random/randomdev_soft.c	(revision 219714)
+++ sys/dev/random/randomdev_soft.c	(working copy)
@@ -353,8 +353,8 @@ random_yarrow_write(void *buf, int count)
 		chunk = HARVESTSIZE;
 		if (i + chunk >= count)
 			chunk = (u_int)(count - i);
-		random_harvest_internal(get_cyclecount(), (char *)buf + i,
-		    chunk, 0, 0, RANDOM_WRITE);
+		random_harvest_internal(cpu_ticks(), (char *)buf + i, chunk,
+		    0, 0, RANDOM_WRITE);
 	}
 }
 
Index: sys/dev/random/harvest.c
===================================================================
--- sys/dev/random/harvest.c	(revision 219714)
+++ sys/dev/random/harvest.c	(working copy)
@@ -78,17 +78,16 @@ random_yarrow_deinit_harvester(void)
  * Implemented as in indirect call to allow non-inclusion of
  * the entropy device.
  *
- * XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle
- * counters are built in, but on older hardware it will do a real time clock
- * read which can be quite expensive.
+ * XXXRW: cpu_ticks() is cheap on most modern hardware, where cycle counters
+ * are built in, but on older hardware it will do a real time clock read
+ * which can be quite expensive.
  */
 void
 random_harvest(void *entropy, u_int count, u_int bits, u_int frac,
     enum esource origin)
 {
 	if (reap_func)
-		(*reap_func)(get_cyclecount(), entropy, count, bits, frac,
-		    origin);
+		(*reap_func)(cpu_ticks(), entropy, count, bits, frac, origin);
 }
 
 /* Userland-visible version of read_random */
Index: sys/i386/include/cpu.h
===================================================================
--- sys/i386/include/cpu.h	(revision 219714)
+++ sys/i386/include/cpu.h	(working copy)
@@ -39,7 +39,6 @@
 /*
  * Definitions unique to i386 cpu support.
  */
-#include <machine/cputypes.h>
 #include <machine/psl.h>
 #include <machine/frame.h>
 #include <machine/segments.h>
@@ -70,13 +69,8 @@ void	swi_vm(void *);
 static __inline uint64_t
 get_cyclecount(void)
 {
-	struct bintime bt;
 
-	if (cpu_class == CPUCLASS_486) {
-		binuptime(&bt);
-		return ((uint64_t)bt.sec << 56 | bt.frac >> 8);
-	}
-	return (rdtsc());
+	return (cpu_ticks());
 }
 
 #endif