1 files changed, 34 insertions, 0 deletions

diff --git a/patches/boot_time_opt_guest/0102-cpuidle-skip-synchronize_rcu-on-single-CPU-systems.patch b/patches/boot_time_opt_guest/0102-cpuidle-skip-synchronize_rcu-on-single-CPU-systems.patch
new file mode 100644
index 0000000..1de2a6b
--- /dev/null
+++ b/patches/boot_time_opt_guest/0102-cpuidle-skip-synchronize_rcu-on-single-CPU-systems.patch
@@ -0,0 +1,34 @@
+From 6b0fb5b2a7a157c04d8ab6ad71b092034d0048bf Mon Sep 17 00:00:00 2001
+From: Arjan van de Ven <arjan@linux.intel.com>
+Date: Wed, 11 Feb 2015 16:19:26 -0600
+Subject: [PATCH 102/114] cpuidle: skip synchronize_rcu() on single CPU systems
+
+synchronize_rcu() is pretty expensive, and on single CPU systems we don't need
+it in this specific case, so skip it.
+
+Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
+Signed-off-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
+---
+ drivers/cpuidle/cpuidle.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
+index 62810ff3b00f..f1d110411098 100644
+--- a/drivers/cpuidle/cpuidle.c
++++ b/drivers/cpuidle/cpuidle.c
+@@ -324,8 +324,11 @@ void cpuidle_uninstall_idle_handler(void)
+        /*
+         * Make sure external observers (such as the scheduler)
+         * are done looking at pointed idle states.
++        * This is only relevant if there is more than one cpu,
++        * if there is only one CPU, that is us... and we're
++        * coherent to ourselves.
+         */
+-       synchronize_rcu();
++
+ }
+ 
+ /**
+-- 
+2.11.1
+