commit 1996990f769bcb02c4eea6ef774484052ff7e68e
author Nicholas Piggin <npiggin@gmail.com> Sun Oct 03 11:22:04 2021 +1000
committer Vasant Hegde <hegdevasant@linux.vnet.ibm.com> Tue Oct 19 12:08:19 2021 +0530
tree 7f8621b53396f96fc28c0536925b9fcf22ba9eba
parent 1f8cc710c830f8642d74f09392dbe106377fa1b1

cpu: cpu_idle_job SMT priority fix

Calling cpu_relax resets the SMT priority to medium, causing the idle
loop not to run with lowest priority. Just use barrier() instead, this
saves about 3 seconds on a SMT4 systemsim (mambo) boot.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>

core/cpu.c

diff --git a/core/cpu.c b/core/cpu.c
index f58aeb2..5c10fc6 100644
--- a/core/cpu.c
+++ b/core/cpu.c
@@ -547,7 +547,6 @@
 		while (!cpu_check_jobs(cpu)) {
 			if (pm_enabled)
 				break;
-			cpu_relax();
 			barrier();
 		}
 		smt_medium();