Messages in this thread | | | Date | Sat, 23 Jul 2005 16:40:46 -0700 | From | randy_dunlap <> | Subject | Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt |
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On Sat, 16 Jul 2005 23:55:17 -0400 Lee Revell wrote:
> On Sat, 2005-07-16 at 19:35 -0700, Nish Aravamudan wrote: > > As you've seen, I think it depends on the timesource: for the PIT, it > > would be arch/i386/kernel/timers/timer_pit.c::setup_pit_timer(). > > That one looks pretty straightforward. > arch/i386/kernel/timers/timer_tsc.c really looks like fun. So many > corner cases... > > BTW shouldn't this code from mark_offset_tsc(): > > 402 if (pit_latch_buggy) { > 403 /* get center value of last 3 time lutch */ > 404 if ((count2 >= count && count >= count1) > 405 || (count1 >= count && count >= count2)) { > 406 count2 = count1; count1 = count; > 407 } else if ((count1 >= count2 && count2 >= count) > 408 || (count >= count2 && count2 >= count1)) { > 409 countmp = count;count = count2; > 410 count2 = count1;count1 = countmp; > 411 } else { > 412 count2 = count1; count1 = count; count = count1; > 413 } > 414 } > > use an ifdef? It only applies to cyrix_55x0, and mark_offset_tsc is a > pretty hot path.
I see your point, but several distros build kernels that run on almost any x86-32 machine, so I think that it's there as is for universal-kernel support.
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