[src/trunk]: src/sys/arch/xen/xen xen_clock(4): New hardclock dtrace probes.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/bbd34956286c
branches:  trunk
changeset: 378259:bbd34956286c
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Jul 28 10:39:14 2023 +0000

description:
xen_clock(4): New hardclock dtrace probes.

sdt:xen:hardclock:tick(last, now)
  fires on every hardclock tick

sdt:xen:hardclock:jump(last, now, nticks)
  fires on every hardclock tick when (now - last) >= 2*NS_PER_TICK,
  i.e., this call to the timer interrupt handler requires multiple
  hardclock ticks

diffstat:

 sys/arch/xen/xen/xen_clock.c |  18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)

diffs (53 lines):

diff -r e14531b5f2ed -r bbd34956286c sys/arch/xen/xen/xen_clock.c
--- a/sys/arch/xen/xen/xen_clock.c      Fri Jul 28 10:39:01 2023 +0000
+++ b/sys/arch/xen/xen/xen_clock.c      Fri Jul 28 10:39:14 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: xen_clock.c,v 1.14 2023/07/28 10:39:01 riastradh Exp $ */
+/*     $NetBSD: xen_clock.c,v 1.15 2023/07/28 10:39:14 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 1.14 2023/07/28 10:39:01 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xen_clock.c,v 1.15 2023/07/28 10:39:14 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -120,6 +120,13 @@ SDT_PROBE_DEFINE3(sdt, xen, timecounter,
 SDT_PROBE_DEFINE2(sdt, xen, hardclock, systime__backward,
     "uint64_t"/*last_systime_ns*/,
     "uint64_t"/*this_systime_ns*/);
+SDT_PROBE_DEFINE2(sdt, xen, hardclock, tick,
+    "uint64_t"/*last_systime_ns*/,
+    "uint64_t"/*this_systime_ns*/);
+SDT_PROBE_DEFINE3(sdt, xen, hardclock, jump,
+    "uint64_t"/*last_systime_ns*/,
+    "uint64_t"/*this_systime_ns*/,
+    "uint64_t"/*nticks*/);
 SDT_PROBE_DEFINE3(sdt, xen, hardclock, missed,
     "uint64_t"/*last_systime_ns*/,
     "uint64_t"/*this_systime_ns*/,
@@ -800,7 +807,8 @@ again:
         */
        last = ci->ci_xen_hardclock_systime_ns;
        now = xen_vcputime_systime_ns();
-       if (now < last) {
+       SDT_PROBE2(sdt, xen, hardclock, tick,  last, now);
+       if (__predict_false(now < last)) {
                SDT_PROBE2(sdt, xen, hardclock, systime__backward,
                    last, now);
 #if XEN_CLOCK_DEBUG
@@ -818,6 +826,10 @@ again:
         * times as appears necessary based on how much time has
         * passed.
         */
+       if (__predict_false(delta >= 2*ns_per_tick)) {
+               SDT_PROBE3(sdt, xen, hardclock, jump,
+                   last, now, delta/ns_per_tick);
+       }
        while (delta >= ns_per_tick) {
                ci->ci_xen_hardclock_systime_ns += ns_per_tick;
                delta -= ns_per_tick;