@Viresh Kumar: Thank you for taking time out to resolve my questions. @Vincent Guittot: I have not looked into the devfreq framework. Thank you for pointing me towards it. I will try to use this framework to implement the proposed memory frequency scaling. I have only been working on the Linux kernel a few months, but it seems to me that Linux has thought of everything already! Regards Guru On Thu, Jun 27, 2013 at 4:11 AM, Vincent Guittot <vincent.guittot@xxxxxxxxxx> wrote: > On 26 June 2013 17:58, Guru Prasad <gurupras@xxxxxxxxxxx> wrote: >> Hi, >> >> I'm working with a hardware simulator - Gem5 (http://gem5.org). I have >> added some functionality to this simulator to modify memory frequency. >> >> I would like to add kernel support to manage memory frequency similar >> to how cpu frequency is currently maintained so that I can study the >> cost-benefit of memory frequency scaling. > > Have you looked at devfreq framework ? It should match with what you > are looking for. > > devfreq is used to manage the frequency scaling of devices other than > cpu like the gpu or the memory > > Vincent > > >> >> I copied all the generic cpufreq sources to a separate folder >> kernel_source/drivers/memfreq and setup the drivers/Makefile. I have >> also done the preliminary Kconfig modifications. >> >> A few things I don't follow are >> >> Where does the kernel actually implement the delay resulting from >> cpuinfo.transition_latency? >> Does the kernel stall for the duration of the delay? >> >> the per_cpu macro - I don't understand what this does..How can >> I implement the same for memory - which I'm considering as a shared >> resource rather than per_cpu. >> >> the subsys interface - What does it do and how do I reproduce >> this for memory? Can I use the existing bus_type memory_subsys? >> (drivers/base/memory.c) >> >> callback - This seems to be specific for >> CONFIG_HOTPLUG_CPU..do I need to implement this at all for memfreq? >> >> sysfs interface - Is there any place I can look to >> implement a nice sysfs interface similar to cpufreq? >> >> >> Please let me know if there is anything I've missed out that might >> complicate the process. >> >> >> Regards >> Guru >> -- >> To unsubscribe from this list: send the line "unsubscribe cpufreq" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
