Fri Jul 24 05:19:14 2015 UTC ()

- fix sc_ev_missing_ticks over-counting.
- don't use 64bit division, because it has expensive cost on gcc/arm
  whether it is a constant or not.

'delta' is usually taken a value around sc_autoinc depending on timing
of read. therefore 'delta / sc->sc_autoinc' would be count too much.


(ryo)

diff -r1.12 -r1.13 src/sys/arch/arm/cortex/a9tmr.c

--- src/sys/arch/arm/cortex/a9tmr.c 2015/03/04 23:18:21	1.12
+++ src/sys/arch/arm/cortex/a9tmr.c 2015/07/24 05:19:13	1.13

 @@ -1,14 +1,14 @@
-/*	$NetBSD: a9tmr.c,v 1.12 2015/03/04 23:18:21 jmcneill Exp $	*/
+/*	$NetBSD: a9tmr.c,v 1.13 2015/07/24 05:19:13 ryo Exp $	*/
 /*-
  * Copyright (c) 2012 The NetBSD Foundation, Inc.
  * All rights reserved.
+ *
  * This code is derived from software contributed to The NetBSD Foundation
  * by Matt Thomas
+ *
  * 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.
 @@ -20,27 +20,27 @@
  * ``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 FOUNDATION 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.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: a9tmr.c,v 1.12 2015/03/04 23:18:21 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: a9tmr.c,v 1.13 2015/07/24 05:19:13 ryo Exp $");
 #include <sys/param.h>
 #include <sys/bus.h>
 #include <sys/device.h>
 #include <sys/intr.h>
 #include <sys/kernel.h>
 #include <sys/proc.h>
 #include <sys/systm.h>
 #include <sys/timetc.h>
 #include <sys/xcall.h>
 #include <prop/proplib.h>
 @@ -319,48 +319,50 @@ clockhandler(void *arg)
 	struct clockframe * const cf = arg;
 	struct a9tmr_softc * const sc = &a9tmr_sc;
 	struct cpu_info * const ci = curcpu();
 	const uint64_t now = a9tmr_gettime(sc);
 	uint64_t delta = now - ci->ci_lastintr;
 	a9tmr_global_write(sc, TMR_GBL_INT, 1);	// Ack the interrupt
 #if 0
 	printf("%s(%p): %s: now %#"PRIx64" delta %"PRIu64"\n",
 	     __func__, cf, ci->ci_data.cpu_name, now, delta);
 #endif
-	KASSERTMSG(delta > sc->sc_autoinc / 100,
+	KASSERTMSG(delta > sc->sc_autoinc / 64,
 	    "%s: interrupting too quickly (delta=%"PRIu64")",
 	    ci->ci_data.cpu_name, delta);
 	ci->ci_lastintr = now;
 	hardclock(cf);
 	if (delta > sc->sc_autoinc) {
 		u_int ticks = hz;
 		for (delta -= sc->sc_autoinc;
 		     delta >= sc->sc_autoinc && ticks > 0;
 		     delta -= sc->sc_autoinc, ticks--) {
 #if 0
-	/*
+			/*
-	 * Try to make up up to a seconds amount of missed clock interrupts
+			 * Try to make up up to a seconds amount of
-	 */
+			 * missed clock interrupts
-	u_int ticks = hz;
+			 */
-	for (delta -= sc->sc_autoinc;
+			hardclock(cf);
 	     ticks > 0 && delta >= sc->sc_autoinc;
 	     delta -= sc->sc_autoinc, ticks--) {
 		hardclock(cf);
 #else
-	if (delta > sc->sc_autoinc)
+			sc->sc_ev_missing_ticks.ev_count++;
 		sc->sc_ev_missing_ticks.ev_count += delta / sc->sc_autoinc;
 #endif
+		}
+	}
 	return 1;
+}
 void
 setstatclockrate(int newhz)
+{
+}
 static u_int
 a9tmr_get_timecount(struct timecounter *tc)
+{
 	struct a9tmr_softc * const sc = tc->tc_priv;