From 18c07cf530cf4aa8b7551801f68ed40db5ee4e45 Mon Sep 17 00:00:00 2001 From: Cliff Wickman Date: Thu, 15 Jan 2009 09:51:20 -0600 Subject: x86, UV: cpu_relax in uv_wait_completion The function uv_wait_completion() spins on reads of a memory-mapped register, waiting for completion of BAU hardware replies. It should call "cpu_relax()" between those reads to improve performance on hyperthreaded configurations. Signed-off-by: Cliff Wickman Acked-by: Jack Steiner Signed-off-by: Ingo Molnar --- arch/x86/kernel/tlb_uv.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86') diff --git a/arch/x86/kernel/tlb_uv.c b/arch/x86/kernel/tlb_uv.c index f885023167e..6812b829ed8 100644 --- a/arch/x86/kernel/tlb_uv.c +++ b/arch/x86/kernel/tlb_uv.c @@ -200,6 +200,7 @@ static int uv_wait_completion(struct bau_desc *bau_desc, destination_timeouts = 0; } } + cpu_relax(); } return FLUSH_COMPLETE; } -- cgit v1.2.3