From: Christoph Hellwig <hch@lst.de>
Date: Fri, 23 Mar 2007 14:12:26 +0000 (+0100)
Subject: [POWERPC] spufs: don't yield CPU in spu_yield
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=dbf8eefa2b814d6922492120bfa46d4bc42ceb20;p=openwrt%2Fstaging%2Fblogic.git

[POWERPC] spufs: don't yield CPU in spu_yield

There is no reason to yield the CPU in spu_yield - if the backing
thread reenters spu_run it gets added to the end of the runqueue for
it's priority.  So the yield is just a slowdown for the case where
we have higher priority contexts waiting.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
---

diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 39823cec0844..c9561582ce2a 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -438,7 +438,6 @@ void spu_deactivate(struct spu_context *ctx)
 void spu_yield(struct spu_context *ctx)
 {
 	struct spu *spu;
-	int need_yield = 0;
 
 	if (mutex_trylock(&ctx->state_mutex)) {
 		if ((spu = ctx->spu) != NULL) {
@@ -447,13 +446,10 @@ void spu_yield(struct spu_context *ctx)
 				pr_debug("%s: yielding SPU %d NODE %d\n",
 					 __FUNCTION__, spu->number, spu->node);
 				spu_deactivate(ctx);
-				need_yield = 1;
 			}
 		}
 		mutex_unlock(&ctx->state_mutex);
 	}
-	if (unlikely(need_yield))
-		yield();
 }
 
 int __init spu_sched_init(void)