diff options
| author | Scott Soule Cheloha <cheloha@cvs.openbsd.org> | 2023-03-08 18:05:06 +0000 |
|---|---|---|
| committer | Scott Soule Cheloha <cheloha@cvs.openbsd.org> | 2023-03-08 18:05:06 +0000 |
| commit | ad8ff96b086eb1eb8fb13c56a2fb17d66e84654e (patch) | |
| tree | 2fa26dbc6e56c5fb3b1668995b5e2d31a65e47a8 /sys/arch | |
| parent | 0add3f7404b4d07c43880a86b8fa57a2d9eeb4b2 (diff) | |
amd64: lapic_timer_rearm: don't reset mode, mask, divisor
The apic timer mode, mask, and divisor are set during lapic_timer_trigger().
We don't need to reset them when rearming the timer. On physical hardware
the difference is too small to measure, but skipping two apic writes may be
a bit faster when we're running in a VM.
Bochs also likes to log when the apic divisor is changed:
38569516308i[APIC0 ] set timer divide factor to 1
38569517335i[APIC0 ] set timer divide factor to 1
38569518042i[APIC0 ] set timer divide factor to 1
[...]
With this change, Bochs is a lot less noisy.
Idea from mlarkin@.
ok mlarkin@
Diffstat (limited to 'sys/arch')
| -rw-r--r-- | sys/arch/amd64/amd64/lapic.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sys/arch/amd64/amd64/lapic.c b/sys/arch/amd64/amd64/lapic.c index 6c8ccdf2658..a5d6d28832f 100644 --- a/sys/arch/amd64/amd64/lapic.c +++ b/sys/arch/amd64/amd64/lapic.c @@ -1,4 +1,4 @@ -/* $OpenBSD: lapic.c,v 1.66 2023/01/31 19:11:47 cheloha Exp $ */ +/* $OpenBSD: lapic.c,v 1.67 2023/03/08 18:05:05 cheloha Exp $ */ /* $NetBSD: lapic.c,v 1.2 2003/05/08 01:04:35 fvdl Exp $ */ /*- @@ -431,7 +431,7 @@ lapic_timer_rearm(void *unused, uint64_t nsecs) cycles = (nsecs * lapic_timer_nsec_cycle_ratio) >> 32; if (cycles == 0) cycles = 1; - lapic_timer_oneshot(0, cycles); + lapic_writereg(LAPIC_ICR_TIMER, cycles); } void |