Messages in this thread | | | Subject | Re: How is user space notified of CPU speed changes? | From | Lee Revell <> | Date | Sat, 23 Oct 2004 21:40:56 -0400 |
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On Sun, 2004-10-24 at 00:17 +0100, Jon Masters wrote: > On Sat, 23 Oct 2004 18:42:13 -0400, Lee Revell <rlrevell@joe-job.com> wrote: > > > Does anyone know how OSX/CoreAudio handles the situation? Apparently > > realtime apps work flawlessly on speed scaling laptops under OSX. > > The difference in implementation between the Intel TSC and PowerPC > TB[LU] has been mentioned previously in this thread.
Well, it was mentioned that there is a difference...
http://www-106.ibm.com/developerworks/eserver/pdfs/archpub2.pdf
pg. 39, "Non-constant update frequency".
"Each time the update frequency changes, the system software is notified of the change via an interrupt, or the change was instigated by the system software itself. At each such change, the system software must compute the current time of day using the old update frequency, compute a new value of ticks_per_sec for the new frequency, and save the time of day, Time Base value, and the tick rate"
This was what I wanted to know: does Linux and/or the x86 have a similar mechanism? Looks like the answer is no...
Lee
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