[Xen-changelog] [xen master] xen: credit2: "relax" CSCHED2_MAX_TIMER

[patchbot@xxxxxxx]

commit da92ec5bd13b7d0a7093a251a6535f21c7a6ad0e
Author:     Dario Faggioli <dario.faggioli@xxxxxxxxxx>
AuthorDate: Thu Sep 15 12:35:05 2016 +0100
Commit:     George Dunlap <george.dunlap@xxxxxxxxxx>
CommitDate: Fri Sep 30 16:32:05 2016 +0100

    xen: credit2: "relax" CSCHED2_MAX_TIMER
    
    Credit2 is already event based, rather than tick
    based. This means, the time at which the (i+1)-eth
    scheduling decision needs to happen is computed
    during the i-eth scheduling decision, and a timer
    is set accordingly.
    
    If there's nothing imminent (or, the most imminent
    event is really really really far away), it is
    ok to say "well, let's double-check things in
    a little bit anyway", but such 'little bit' does
    not need to be too little, as, most likely, it's
    just pure overhead.
    
    The current period, for this "safety catch"-alike
    timer is 2ms, which indeed is high, but it can
    well be higher. In fact, benchmarks show that
    setting it to 10ms --combined with other
    optimizations-- does actually improve performance.
    
    Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
    Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
---
 xen/common/sched_credit2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 6b98319..fe46e80 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -149,7 +149,7 @@
 /* Reset: Value below which credit will be reset. */
 #define CSCHED2_CREDIT_RESET         0
 /* Max timer: Maximum time a guest can be run for. */
-#define CSCHED2_MAX_TIMER            MILLISECS(2)
+#define CSCHED2_MAX_TIMER            CSCHED2_CREDIT_INIT
 
 
 #define CSCHED2_IDLE_CREDIT                 (-(1<<30))
--
generated by git-patchbot for /home/xen/git/xen.git#master

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