@@ -203,12 +203,12 @@ The default mode (tsc_mode==0) checks TSC-safeness of the underlying
hardware on which the virtual machine is launched. If it is
TSC-safe, rdtsc will execute at hardware speed; if it is not, rdtsc
will be emulated. Once a virtual machine is save/restored or migrated,
-however, there are two possibilities: For a paravirtualized (PV) domain,
-TSC will always be emulated. For a fully-virtualized (HVM) domain,
-TSC remains native IF the source physical machine and target physical machine
-have the same TSC frequency; else TSC is emulated. Note that, though
-emulated, the "apparent" TSC frequency will be the TSC frequency
-of the initial physical machine, even after migration.
+however, there are two possibilities: TSC remains native IF the source
+physical machine and target physical machine have the same TSC frequency
+(or, for HVM/PVH guests, if TSC scaling support is available); else TSC
+is emulated. Note that, though emulated, the "apparent" TSC frequency
+will be the TSC frequency of the initial physical machine, even after
+migration.
For environments where both TSC-safeness AND highest performance
even across migration is a requirement, application code can be specially
A number of changes have been made to how we determine whether TSC is emulated (e.g. commit 4fc380ac0077 ("x86/time: don't use virtual TSC if host and guest frequencies are equal")). Update the man page to reflect those changes Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Olaf Hering <olaf@aepfle.de> --- docs/man/xen-tscmode.pod.7 | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)