[Xen-devel] [RFC 6/9] sched:rtds: get guest time from time accounting code

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

From: Andrii Anisov <andrii_anisov@xxxxxxxx>

While the RTDS scheduler code does not use guest time from the
other pcpu, we are free to go with lockless time accounting.

Signed-off-by: Andrii Anisov <andrii_anisov@xxxxxxxx>
---
 xen/common/sched_rt.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index e0e350b..2ce200b 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -945,8 +945,9 @@ burn_budget(const struct scheduler *ops, struct rt_vcpu 
*svc, s_time_t now)
     if ( is_idle_vcpu(svc->vcpu) )
         return;
 
+    ASSERT(svc->vcpu == current);
     /* burn at nanoseconds level */
-    delta = now - svc->last_start;
+    delta = tacc_get_guest_time_delta();
     /*
      * delta < 0 only happens in nested virtualization;
      * TODO: how should we handle delta < 0 in a better way?
@@ -960,7 +961,6 @@ burn_budget(const struct scheduler *ops, struct rt_vcpu 
*svc, s_time_t now)
     }
 
     svc->cur_budget -= delta;
-    svc->last_start = now;
 
     if ( svc->cur_budget <= 0 )
     {
-- 
2.7.4


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