patches: Boot time optimizations with ClearLinux patches

Signed-off-by: Adrian Calianu <adrian.calianu@enea.com>
Signed-off-by: Adrian Dudau <adrian.dudau@enea.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/patches/boot_time_opt/0113-overload-on-wakeup.patch b/patches/boot_time_opt/0113-overload-on-wakeup.patch
new file mode 100644
index 0000000..a3a6bce
--- /dev/null
+++ b/patches/boot_time_opt/0113-overload-on-wakeup.patch
@@ -0,0 +1,43 @@
+From 9f25d18f45a8391488feb9783404f2f79b7090f4 Mon Sep 17 00:00:00 2001
+From: jplozi <jplozi@unice.fr>
+Date: Fri, 11 Mar 2016 15:18:06 +0100
+Subject: [PATCH 113/124] overload on wakeup
+
+source https://github.com/jplozi/wastedcores
+
+as an experiment, apply the learnings from the wasted-cores paper
+and see how the performance works out. With the data from this we should
+be able to work with Peter and the rest of the scheduler folks on
+a more permanent/elegant solution.
+---
+ kernel/sched/fair.c | 14 ++++++++++++++
+ 1 file changed, 14 insertions(+)
+
+diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
+index c242944f5cbd..5132c828161e 100644
+--- a/kernel/sched/fair.c
++++ b/kernel/sched/fair.c
+@@ -5638,6 +5638,20 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
+        }
+ 
+        rcu_read_lock();
++
++       if (cpu_rq(prev_cpu)->nr_running) {
++               int _cpu;
++
++               for_each_online_cpu(_cpu) {
++                       if (!cpumask_test_cpu(_cpu, tsk_cpus_allowed(p)) ||
++                               cpu_rq(_cpu)->nr_running)
++                               continue;
++
++                       rcu_read_unlock();
++                       return _cpu;
++               }
++       }
++
+        for_each_domain(cpu, tmp) {
+                if (!(tmp->flags & SD_LOAD_BALANCE))
+                        break;
+-- 
+2.11.1
+