Author: marius
Date: Sun Oct 17 16:46:54 2010
New Revision: 213985
URL: http://svn.freebsd.org/changeset/base/213985
Log:
- In oneshot-mode it doesn't make sense to try to compensate the clock
drift in order to achieve a more stable clock as the tick intervals may
vary in the first place. In fact I haven't seen this code kick in when
in oneshot-mode so just skip it in that case.
- There's no need to explicitly stop the (S)TICK counter in oneshot-mode
with every tick as it just won't trigger again with the (S)TICK compare
register set to a value in the past (with a wrap-around once every ~195
years of uptime at 1.5 GHz this isn't something we have to worry about
in practice).
- Given that we'll disable interrupts completely anyway there's no
need to enter critical sections.
Modified:
head/sys/sparc64/sparc64/tick.c
Modified: head/sys/sparc64/sparc64/tick.c
==============================================================================
--- head/sys/sparc64/sparc64/tick.c Sun Oct 17 16:43:20 2010
(r213984)
+++ head/sys/sparc64/sparc64/tick.c Sun Oct 17 16:46:54 2010
(r213985)
@@ -96,8 +96,8 @@ static int tick_et_start(struct eventtim
static int tick_et_stop(struct eventtimer *et);
static void tick_intr(struct trapframe *tf);
static void tick_intr_bbwar(struct trapframe *tf);
-static inline void tick_hardclock_common(struct trapframe *tf, u_long tick,
- u_long adj);
+static inline void tick_hardclock_periodic(struct trapframe *tf, u_long tick,
+ u_long tick_increment, u_long adj);
static inline void tick_process(struct trapframe *tf);
static void stick_intr(struct trapframe *tf);
@@ -225,18 +225,18 @@ tick_intr(struct trapframe *tf)
u_long adj, tick, tick_increment;
register_t s;
- critical_enter();
- adj = PCPU_GET(tickadj);
- tick_increment = PCPU_GET(tickincrement);
s = intr_disable();
- tick = rd(tick);
- if (tick_increment != 0)
+ tick_increment = PCPU_GET(tickincrement);
+ if (tick_increment != 0) {
+ adj = PCPU_GET(tickadj);
+ tick = rd(tick);
wr(tick_cmpr, tick + tick_increment - adj, 0);
- else
- wr(tick_cmpr, 1L << 63, 0);
- intr_restore(s);
- tick_hardclock_common(tf, tick, adj);
- critical_exit();
+ intr_restore(s);
+ tick_hardclock_periodic(tf, tick, tick_increment, adj);
+ } else {
+ intr_restore(s);
+ tick_process(tf);
+ }
}
static void
@@ -245,18 +245,18 @@ tick_intr_bbwar(struct trapframe *tf)
u_long adj, tick, tick_increment;
register_t s;
- critical_enter();
- adj = PCPU_GET(tickadj);
- tick_increment = PCPU_GET(tickincrement);
s = intr_disable();
- tick = rd(tick);
- if (tick_increment != 0)
+ tick_increment = PCPU_GET(tickincrement);
+ if (tick_increment != 0) {
+ adj = PCPU_GET(tickadj);
+ tick = rd(tick);
wrtickcmpr(tick + tick_increment - adj, 0);
- else
- wrtickcmpr(1L << 63, 0);
- intr_restore(s);
- tick_hardclock_common(tf, tick, adj);
- critical_exit();
+ intr_restore(s);
+ tick_hardclock_periodic(tf, tick, tick_increment, adj);
+ } else {
+ intr_restore(s);
+ tick_process(tf);
+ }
}
static void
@@ -265,28 +265,28 @@ stick_intr(struct trapframe *tf)
u_long adj, stick, tick_increment;
register_t s;
- critical_enter();
- adj = PCPU_GET(tickadj);
- tick_increment = PCPU_GET(tickincrement);
s = intr_disable();
- stick = rdstick();
- if (tick_increment != 0)
+ tick_increment = PCPU_GET(tickincrement);
+ if (tick_increment != 0) {
+ adj = PCPU_GET(tickadj);
+ stick = rdstick();
wrstickcmpr(stick + tick_increment - adj, 0);
- else
- wrstickcmpr(1L << 63, 0);
- intr_restore(s);
- tick_hardclock_common(tf, stick, adj);
- critical_exit();
+ intr_restore(s);
+ tick_hardclock_periodic(tf, stick, tick_increment, adj);
+ } else {
+ intr_restore(s);
+ tick_process(tf);
+ }
}
static inline void
-tick_hardclock_common(struct trapframe *tf, u_long tick, u_long adj)
+tick_hardclock_periodic(struct trapframe *tf, u_long tick,
+ u_long tick_increment, u_long adj)
{
- u_long ref, tick_increment;
+ u_long ref;
long delta;
int count;
- tick_increment = PCPU_GET(tickincrement);
ref = PCPU_GET(tickref);
delta = tick - ref;
count = 0;
@@ -297,8 +297,6 @@ tick_hardclock_common(struct trapframe *
if (adj != 0)
adjust_ticks++;
count++;
- if (tick_increment == 0)
- break;
}
if (count > 0) {
adjust_missed += count - 1;
@@ -361,11 +359,10 @@ tick_get_timecount_mp(struct timecounter
#endif
static int
-tick_et_start(struct eventtimer *et,
- struct bintime *first, struct bintime *period)
+tick_et_start(struct eventtimer *et, struct bintime *first,
+ struct bintime *period)
{
- u_long fdiv, div;
- u_long base;
+ u_long base, div, fdiv;
register_t s;
if (period != NULL) {
@@ -387,22 +384,21 @@ tick_et_start(struct eventtimer *et,
* on all CPUs to avoid inaccuracies for migrating processes. Leave
* out one tick to make sure that it is not missed.
*/
- critical_enter();
- PCPU_SET(tickadj, 0);
s = intr_disable();
if (hardclock_use_stick != 0)
base = rdstick();
else
base = rd(tick);
- if (div != 0)
+ if (div != 0) {
+ PCPU_SET(tickadj, 0);
base = roundup(base, div);
+ }
PCPU_SET(tickref, base);
if (hardclock_use_stick != 0)
wrstickcmpr(base + fdiv, 0);
else
wrtickcmpr(base + fdiv, 0);
intr_restore(s);
- critical_exit();
return (0);
}
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