Add a sched_clock paravirt_op
The tsc-based get_scheduled_cycles interface is not a good match for
Xen's runstate accounting, which reports everything in nanoseconds.
This patch replaces this interface with a sched_clock interface, which
matches both Xen and VMI's requirements.
In order to do this, we:
1. replace get_scheduled_cycles with sched_clock
2. hoist cycles_2_ns into a common header
3. update vmi accordingly
One thing to note: because sched_clock is implemented as a weak
function in kernel/sched.c, we must define a real function in order to
override this weak binding. This means the usual paravirt_ops
technique of using an inline function won't work in this case.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Dan Hecht <dhecht@vmware.com>
Cc: john stultz <johnstul@us.ibm.com>
diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c
index 60e08b9..53f07a8 100644
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -302,7 +302,7 @@
.write_msr = native_write_msr_safe,
.read_tsc = native_read_tsc,
.read_pmc = native_read_pmc,
- .get_scheduled_cycles = native_read_tsc,
+ .sched_clock = native_sched_clock,
.get_cpu_khz = native_calculate_cpu_khz,
.load_tr_desc = native_load_tr_desc,
.set_ldt = native_set_ldt,