Commit 18c07cf5 authored Jan 15, 2009 by Cliff Wickman Committed by Ingo Molnar Jan 15, 2009

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 <cpw@sgi.com>
Acked-by: Jack Steiner <steiner@sgi.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 4a13ad0b

arch/x86/kernel/tlb_uv.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -200,6 +200,7 @@ static int uv_wait_completion(struct bau_desc *bau_desc,
		destination_timeouts = 0;
		}
		}
		cpu_relax();
		}
		return FLUSH_COMPLETE;
		}