Re: lmbench context switch regression

From: Nick Piggin
Date: Wed Nov 05 2003 - 18:21:05 EST

Nick Piggin wrote:

I'm seeing quite a large context switch speed regression as reported
by lmbench when I patched from test9 to test9-mm2.

The obvious thing I can see from the patch is the PF_DEAD finish_task_switch
change. I don't have time to investigate further tonight though.

lmbench two 0 sized processes context switch times go from around 1.80us to
2.60us on my PIII 650 (UP).

The regression is smaller when going from test9 to test9-bk. About .2us (10%).
It does not go away when reverting the PF_DEAD change. Maybe its just lucky

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