From: Dario Faggioli <dario.faggioli@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: George Dunlap <dunlapg@umich.edu>, Tianyang Chen <tiche@seas.upenn.edu>
Subject: [PATCH 11/16] xen: sched: on Credit2, don't reprogram the timer if idle
Date: Fri, 18 Mar 2016 20:05:21 +0100 [thread overview]
Message-ID: <20160318190521.8117.21983.stgit@Solace.station> (raw)
In-Reply-To: <20160318185524.8117.74837.stgit@Solace.station>
as other schedulers are doing already: if the idle vcpu
is picked and scheduled, there is no need to reprogram the
scheduler timer to fire and invoke csched2_schedule()
again in future.
Tickling or external events will serve as pokes, when
necessary, but until we can, we should just stay idle.
Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Reported-by: Tianyang Chen <tiche@seas.upenn.edu>
Suggested-by: George Dunlap <dunlapg@umich.edu>
---
Cc: George Dunlap <dunlapg@umich.edu>
Cc: Tianyang Chen <tiche@seas.upenn.edu>
---
xen/common/sched_credit2.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 2fd4175..4ff26c9 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -1540,8 +1540,12 @@ csched2_runtime(const struct scheduler *ops, int cpu, struct csched2_vcpu *snext
struct csched2_runqueue_data *rqd = RQD(ops, cpu);
struct list_head *runq = &rqd->runq;
+ /*
+ * If we're idle, just stay so. Others (or external events)
+ * will poke us when necessary.
+ */
if ( is_idle_vcpu(snext->vcpu) )
- return CSCHED2_MAX_TIMER;
+ return -1;
/* General algorithm:
* 1) Run until snext's credit will be 0
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next prev parent reply other threads:[~2016-03-18 19:05 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-18 19:03 [PATCH 00/16] Fixes and improvement (including hard affinity!) for Credit2 Dario Faggioli
2016-03-18 19:04 ` [PATCH 01/16] xen: sched: fix locking when allocating an RTDS pCPU Dario Faggioli
2016-03-19 2:22 ` Meng Xu
2016-03-23 15:37 ` George Dunlap
2016-03-18 19:04 ` [PATCH 02/16] xen: sched: add .init_pdata hook to the scheduler interface Dario Faggioli
2016-03-22 8:08 ` Juergen Gross
2016-03-23 17:32 ` George Dunlap
2016-03-18 19:04 ` [PATCH 03/16] xen: sched: make implementing .alloc_pdata optional Dario Faggioli
2016-03-19 2:23 ` Meng Xu
2016-03-21 14:22 ` Jan Beulich
2016-03-23 17:36 ` George Dunlap
2016-03-24 9:43 ` Jan Beulich
2016-03-24 13:14 ` Dario Faggioli
2016-03-21 14:48 ` Juergen Gross
2016-03-21 15:07 ` Jan Beulich
2016-04-01 17:01 ` Dario Faggioli
2016-04-04 4:21 ` Juergen Gross
2016-04-04 6:13 ` Jan Beulich
2016-04-05 16:01 ` Dario Faggioli
2016-03-23 17:38 ` George Dunlap
2016-03-18 19:04 ` [PATCH 04/16] xen: sched: implement .init_pdata in all schedulers Dario Faggioli
2016-03-19 2:24 ` Meng Xu
2016-03-22 8:03 ` Juergen Gross
2016-03-23 17:46 ` George Dunlap
2016-03-18 19:04 ` [PATCH 05/16] xen: sched: move pCPU initialization in an helper Dario Faggioli
2016-03-23 17:51 ` George Dunlap
2016-03-23 18:09 ` George Dunlap
2016-03-24 13:21 ` Dario Faggioli
2016-03-18 19:04 ` [PATCH 06/16] xen: sched: prepare a .switch_sched hook for Credit1 Dario Faggioli
2016-03-18 19:04 ` [PATCH 07/16] xen: sched: prepare a .switch_sched hook for Credit2 Dario Faggioli
2016-03-18 19:04 ` [PATCH 08/16] " Dario Faggioli
2016-03-19 2:24 ` Meng Xu
2016-03-21 14:25 ` Jan Beulich
2016-03-18 19:05 ` [PATCH 09/16] xen: sched: close potential races when switching scheduler to CPUs Dario Faggioli
2016-03-19 2:25 ` Meng Xu
2016-03-23 19:05 ` George Dunlap
2016-04-05 16:26 ` Dario Faggioli
2016-04-06 15:51 ` Dario Faggioli
2016-03-24 12:14 ` George Dunlap
2016-04-05 17:37 ` Dario Faggioli
2016-04-06 16:21 ` Dario Faggioli
2016-03-18 19:05 ` [PATCH 10/16] xen: sched: improve credit2 bootparams' scope, placement and signedness Dario Faggioli
2016-03-21 14:51 ` Juergen Gross
2016-03-24 12:20 ` George Dunlap
2016-03-18 19:05 ` Dario Faggioli [this message]
2016-03-24 15:03 ` [PATCH 11/16] xen: sched: on Credit2, don't reprogram the timer if idle George Dunlap
2016-03-18 19:05 ` [PATCH 12/16] xen: sched: fix per-socket runqueue creation in credit2 Dario Faggioli
2016-03-24 12:24 ` George Dunlap
2016-03-18 19:05 ` [PATCH 13/16] xen: sched: allow for choosing credit2 runqueues configuration at boot Dario Faggioli
2016-03-22 7:46 ` Juergen Gross
2016-03-24 12:36 ` George Dunlap
2016-03-18 19:05 ` [PATCH 14/16] xen: sched: per-core runqueues as default in credit2 Dario Faggioli
2016-03-24 12:37 ` George Dunlap
2016-03-18 19:06 ` [PATCH 15/16] xen: sched: scratch space for cpumasks on Credit2 Dario Faggioli
2016-03-18 19:27 ` Andrew Cooper
2016-03-24 12:44 ` George Dunlap
2016-03-24 12:56 ` Andrew Cooper
2016-03-24 13:10 ` Dario Faggioli
2016-03-18 19:06 ` [PATCH 16/16] xen: sched: implement vcpu hard affinity in Credit2 Dario Faggioli
2016-03-24 15:42 ` George Dunlap
2016-04-05 16:50 ` Dario Faggioli
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