Module Name: src
Committed By: riastradh
Date: Fri Jul 28 10:39:01 UTC 2023
Modified Files:
src/sys/arch/xen/xen: xen_clock.c
Log Message:
xen_clock(4): Compute NS_PER_TICK only once per call.
This involves a division by an unknown number, so let's cache it.
XXX Could do better by precomputing it in xen_resumeclocks, with some
effort to ensure concurrent calls don't stomp on each other.
To generate a diff of this commit:
cvs rdiff -u -r1.13 -r1.14 src/sys/arch/xen/xen/xen_clock.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/xen/xen/xen_clock.c
diff -u src/sys/arch/xen/xen/xen_clock.c:1.13 src/sys/arch/xen/xen/xen_clock.c:1.14
--- src/sys/arch/xen/xen/xen_clock.c:1.13 Fri Jul 28 10:38:44 2023
+++ src/sys/arch/xen/xen/xen_clock.c Fri Jul 28 10:39:01 2023
@@ -1,4 +1,4 @@
-/* $NetBSD: xen_clock.c,v 1.13 2023/07/28 10:38:44 riastradh Exp $ */
+/* $NetBSD: xen_clock.c,v 1.14 2023/07/28 10:39:01 riastradh Exp $ */
/*-
* Copyright (c) 2017, 2018 The NetBSD Foundation, Inc.
@@ -36,7 +36,7 @@
#endif
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xen_clock.c,v 1.13 2023/07/28 10:38:44 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xen_clock.c,v 1.14 2023/07/28 10:39:01 riastradh Exp $");
#include <sys/param.h>
#include <sys/types.h>
@@ -782,6 +782,7 @@ xen_resumeclocks(struct cpu_info *ci)
static int
xen_timer_handler(void *cookie, struct clockframe *frame)
{
+ const uint64_t ns_per_tick = NS_PER_TICK;
struct cpu_info *ci = curcpu();
uint64_t last, now, delta, next;
int error;
@@ -817,11 +818,11 @@ again:
* times as appears necessary based on how much time has
* passed.
*/
- while (delta >= NS_PER_TICK) {
- ci->ci_xen_hardclock_systime_ns += NS_PER_TICK;
- delta -= NS_PER_TICK;
+ while (delta >= ns_per_tick) {
+ ci->ci_xen_hardclock_systime_ns += ns_per_tick;
+ delta -= ns_per_tick;
hardclock(frame);
- if (__predict_false(delta >= NS_PER_TICK)) {
+ if (__predict_false(delta >= ns_per_tick)) {
SDT_PROBE3(sdt, xen, hardclock, missed,
last, now, delta);
ci->ci_xen_missed_hardclock_evcnt.ev_count++;
@@ -833,7 +834,7 @@ again:
* time is in the past, so update our idea of what the Xen
* system time is and try again.
*/
- next = ci->ci_xen_hardclock_systime_ns + NS_PER_TICK;
+ next = ci->ci_xen_hardclock_systime_ns + ns_per_tick;
error = HYPERVISOR_set_timer_op(next);
if (error)
goto again;
