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| author | neel <neel@FreeBSD.org> | 2013-04-10 05:59:07 +0000 |
|---|---|---|
| committer | neel <neel@FreeBSD.org> | 2013-04-10 05:59:07 +0000 |
| commit | 3bab173b64b03e7f4e6226b45da13787c9ea6acf (patch) | |
| tree | 24264be4adf2ff77101e01f0bca54977475d4477 /sys/x86 | |
| parent | ac0cfc7fcb1b51ee6aeacfd676fa6dfbe11eefb5 (diff) | |
| download | FreeBSD-src-3bab173b64b03e7f4e6226b45da13787c9ea6acf.zip FreeBSD-src-3bab173b64b03e7f4e6226b45da13787c9ea6acf.tar.gz | |
Unsynchronized TSCs on the host require special handling in bhyve:
- use clock_gettime(2) as the time base for the emulated ACPI timer instead
of directly using rdtsc().
- don't advertise the invariant TSC capability to the guest to discourage it
from using the TSC as its time base.
Discussed with: jhb@ (about making 'smp_tsc' a global)
Reported by: Dan Mack on freebsd-virtualization@
Obtained from: NetApp
Diffstat (limited to 'sys/x86')
| -rw-r--r-- | sys/x86/x86/tsc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c index 4f67818..0994e9c 100644 --- a/sys/x86/x86/tsc.c +++ b/sys/x86/x86/tsc.c @@ -61,7 +61,7 @@ SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN, TUNABLE_INT("kern.timecounter.invariant_tsc", &tsc_is_invariant); #ifdef SMP -static int smp_tsc; +int smp_tsc; SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc, CTLFLAG_RDTUN, &smp_tsc, 0, "Indicates whether the TSC is safe to use in SMP mode"); TUNABLE_INT("kern.timecounter.smp_tsc", &smp_tsc); |
