From af3b530c037aafcbcc6ed92f65112fab84f11b69 Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Tue, 29 Nov 2011 14:17:27 +0000 Subject: libxl: use named options for tsc_mode. Add an enum at the libxl level with a hopefully descriptive set of names. Deprecate the use of an integer in xl cfg files. Signed-off-by: Ian Campbell Committed-by: Ian Jackson Acked-by: Ian Jackson --- docs/man/xl.cfg.pod.5 | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) (limited to 'docs') diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5 index 3f0c4c9823..7748922e7d 100644 --- a/docs/man/xl.cfg.pod.5 +++ b/docs/man/xl.cfg.pod.5 @@ -491,11 +491,45 @@ compatibility mode on more modern Windows OS). =item B + Specifies how the TSC (Time Stamp Counter) should be provided to the -guest. XXX ??? +guest (X86 only). Specifying this option as a number is +deprecated. Options are: + +=over 4 + +=item B<"default"> + +Guest rdtsc/p executed natively when monotonicity can be guaranteed +and emulated otherwise (with frequency scaled if necessary). + +=item B<"always_emulate"> + +Guest rdtsc/p always emulated at 1GHz (kernel and user). Guest rdtsc/p +always emulated and the virtual TSC will appear to increment (kernel +and user) at a fixed 1GHz rate, regardless of the PCPU HZ rate or +power state; Although there is an overhead associated with emulation +this will NOT affect underlying CPU performance. + +=item B<"native"> + +Guest rdtsc always executed natively (no monotonicity/frequency +guarantees); guest rdtscp emulated at native frequency if unsupported +by h/w, else executed natively. + +=item B<"native_paravirt"> + +Same as B, except xen manages TSC_AUX register so guest can +determine when a restore/migration has occurred and assumes guest +obtains/uses pvclock-like mechanism to adjust for monotonicity and +frequency changes. =back +=back + +Please see F for more information on this option. + =head3 Support for Paravirtualisation of HVM Guests The following options allow Paravirtualised features (such as devices) -- cgit v1.2.3