On Monday, August 08, 2011, MyungJoo Ham wrote: > For a usage example, please look at > http://git.infradead.org/users/kmpark/linux-2.6-samsung/shortlog/refs/heads/devfreq > > In the above git tree, DVFS (dynamic voltage and frequency scaling) mechanism > is applied to the memory bus of Exynos4210 for Exynos4210-NURI boards. > In the example, the LPDDR2 DRAM frequency changes between 133, 266, and 400MHz > and other related clocks simply follow the determined DDR RAM clock. > > The DEVFREQ driver for Exynos4210 memory bus is at > /arch/arm/mach-exynos4/devfreq_bus.c in the git tree. > > In the dd (writing and reading 360MiB) test with NURI board, the memory > throughput was not changed (the performance is not deteriorated) while > the SoC power consumption has been reduced by 1%. When the memory access > is not that intense while the CPU is heavily used, the SoC power consumption > has been reduced by 6%. The power consumption has been compared with the > case using the conventional Exynos4210 CPUFREQ driver, which sets memory > bus frequency according to the CPU core frequency. Besides, when the CPU core > running slow and the memory access is intense, the performance (memory > throughput) has been increased by 11% (with higher SoC power consumption of > 5%). The tested governor is "simple-ondemand". > > MyungJoo Ham (3): > PM: Introduce DEVFREQ: generic DVFS framework with device-specific > OPPs > PM / DEVFREQ: add basic governors > PM / DEVFREQ: add sysfs interface > > Documentation/ABI/testing/sysfs-devices-power | 45 ++ > drivers/base/power/Makefile | 1 + > drivers/base/power/devfreq.c | 555 +++++++++++++++++++++++++ > drivers/base/power/opp.c | 9 + > include/linux/devfreq.h | 111 +++++ > kernel/power/Kconfig | 34 ++ > 6 files changed, 755 insertions(+), 0 deletions(-) > create mode 100644 drivers/base/power/devfreq.c > create mode 100644 include/linux/devfreq.h Are there still any objections to this version of the patchset? Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
