Messages in this thread | | | Subject | Re: [PATCH] linux-2.5.67_lost-tick-fix_A2 | From | john stultz <> | Date | 16 Apr 2003 16:21:36 -0700 |
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On Wed, 2003-04-16 at 16:03, george anzinger wrote: > john stultz wrote: > > Some of the divs and mods being added here might concern folks, but by > > not calling timer->get_offset() in detect_lost_tick() we eliminate much > > of the same math. I did some simple cycle counting and the new code > > comes out on average equivalent or faster. > > I think that if you look at the generated code you may find that there > are NO div in the asm code. The C folks know about scaling to avoid > div especially when the divisor is a constant :)
Indeed you are correct. An objdump of both the timer_tsc.o and timer_cyclone.o code reveals that the only divs occur in init code. I like your argument better then mine :)
thanks -john
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