Hi Tyler, Thanks for your informative and quick reply. It also gives a clear pointer to start my work.
I think for my work I also need to simulate the frequency switch delay. Also I need to see how to group the cores in sets and to increase or decrease the frequency of the set. But to start with I am trying to simulate your older work and to check whether it will be helpful to my project needs.Thanks a lot for your guidance. I will keep you posted. Regards, karthik On Mon, Mar 25, 2013 at 6:52 PM, <[email protected]> wrote: > Hi, > > I made the modifications to MARSS to do this quite some time ago... > though, it seems it never got merged in anywhere...? Anywho, the patch and > a BIOS modification can be found here: > http://cs.binghamton.edu/~tstache1/marss/marss-dvfs.tgz > > It might not apply cleanly anymore; YMMV. That being said, I wrote it > about a year ago, so it shouldn't be that much trouble to shoehorn it back > in. If you manage to do so, please make a patch against master and I'll > gladly apply it to our features branch. > > Barring that, I also uploaded a full-working copy of the MARSS repository > I was using at the time. That being said, it's well-behind the current > master and does not have all the bug-fixes/progress/features we made over > the last year. I'd highly suggest trying to merge it with the current > master if you go this route. That repository can be found here: > http://cs.binghamton.edu/~tstache1/marss/.nobackup/MarssDVFS.tgz > > Couple notes: > * The ACPI tables have to be hard-coded into the BIOS image. I modeled > some AMD processor (forgot which); you may need to adjust the BIOS's > tables if you wish to model some other processor or wish to change the # > of gears/frequencies. > > * I did not write this with Turbo Boost/Core in mind. > > * I did not implement a frequency switch latency/delay; any changes take > effect as soon as the relevant MSRs are written. It shouldn't be much work > to sort this out if you have the need for the additional accuracy or > switch frequencies often. > > * I assume that each core has it's own clock domain. This is not true of > most processors today. > > * You might need to manually modprobe the 'powernow-k8' module to get > things going on some distros. > > Regardless, after you get it up and running, the stats should include > information about how much time you spent in each frequency domain, etc. > > Tyler > > > Hi All, > > > > I am working on a project where I need to dynamically change the > frequency > > of the cores in a multi-core machine. I am trying to develop a custom > > In-kernel governor using the kernel Cpufreq infrastructure in Linux. I > > have > > few questions: > > > > 1) Can I simulate DVFS in MARSS? (I found a previous post from Avadh > which > > says 'yes' but it would be great to have more explanation on this as I am > > basically a OS guy) > > 2) Can I simulate DVFS in MARSS in such a way that each core can run at > > different frequency in a simulated multi-core chip? > > > > It would be great if someone could point me in the right direction. > > > > Thanks for your time, > > karthik > > _______________________________________________ > > http://www.marss86.org > > Marss86-Devel mailing list > > [email protected] > > https://www.cs.binghamton.edu/mailman/listinfo/marss86-devel > > > >
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