Messages in this thread | | | Subject | Re: [patch] x86, tsc: fix SMI induced variation in quick_pit_calibrate() | From | Suresh Siddha <> | Date | Mon, 16 Jan 2012 20:06:04 -0800 |
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On Mon, 2012-01-16 at 17:30 -0800, Linus Torvalds wrote: > On Mon, Jan 16, 2012 at 4:52 PM, Linus Torvalds > <torvalds@linux-foundation.org> wrote: > > > > Hmm. I get the feeling that we should remove that line entirely. > > Yeah, I really cannot come up with a single good reason to keep that > line, and suspect that I was a bit loopy when I wrote it. > > So here's the suggested trivially updated patch. Does this work for people?
It does work. But it is taking almost 105 iterations or so to stabilize. And if I boot the system in power-save mode (lowest p-state), it takes almost 115 iterations to stabilize (close to the 25msec limit). This is on the latest gen platform.
So I suspect we can either go back to 500ppm error tolerance:
if ((d1+d2) >= delta >> 10) continue;
or increase the MAX_QUICK_PIT_MS bit more.
thanks, suresh
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