Re: test_and_set_bit() not atomic forever? [cli/sti in char/vt.c [patch]]
Jamie Lokier (lkd@tantalophile.demon.co.uk)
Sun, 31 May 1998 22:31:20 +0100
Andrew Derrick Balsa wrote:
> Some people build SMP kernels regardless of having a single or more
> processors. With a single processor, the net effect of the extra
> unneeded lock prefix is a double performance loss: 1) a memory cycle
> loss to read each lock prefix 2) since locked instruction cycles are
> noncacheable, this can result in the loss of _many_ clock cycles.
Indeed, especially those aiming to have one kernel run on everything.
Perhaps a fixup table to convert all the `lock's to `nop's at
initialisation time?
-- Jamie
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