core: Make secondary spin and locks use cpu_relax()

This makes secondaries spinning waiting for a job and spinlocks
use cpu_relax() which speeds up the primary thread and thus speeds
up the boot process a bit. Also prettify a bit cpu_relax() implementation

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 4 insertions, 5 deletions

diff --git a/core/cpu.c b/core/cpu.c
index cefb1f0f..f962d7c4 100644
--- a/core/cpu.c
+++ b/core/cpu.c
@@ -67,11 +67,10 @@ void cpu_relax(void)
 	/* Relax a bit to give sibling threads some breathing space */
 	smt_low();
 	smt_very_low();
-	asm volatile("nop; nop; nop\n");
-	asm volatile("nop; nop; nop\n");
-	asm volatile("nop; nop; nop\n");
-	asm volatile("nop; nop; nop\n");
-	asm volatile("nop; nop; nop\n");
+	asm volatile("nop; nop; nop; nop\n");
+	asm volatile("nop; nop; nop; nop\n");
+	asm volatile("nop; nop; nop; nop\n");
+	asm volatile("nop; nop; nop; nop\n");
 	smt_medium();
 }