Messages in this thread | | | Subject | Re: [PATCH 1/3] softirq: Use ffs in __do_softirq | From | Joe Perches <> | Date | Mon, 09 Dec 2013 10:56:46 -0800 |
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On Mon, 2013-12-09 at 19:44 +0100, Frederic Weisbecker wrote: > On Sun, Nov 17, 2013 at 01:55:10AM -0800, Joe Perches wrote: > > Possible speed improvement of the __do_softirq function by using ffs > > instead of using a while loop with an & 1 test then single bit shift. [] > Perhaps using for_each_set_bit() would simplify that more?
It might simplify the appearance of the code but it would/could expand the amount of generated code because for_each_set_bit uses an address_of(unsigned long) and the value tested is an unsigned int.
extra dereferences, can't be in a register, etc...
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