In POWER8, OCC(On-Chip-Controller) can throttle the frequency of the CPU when the chip crosses its thermal and power limits. Currently, powernv-cpufreq driver detects and reports this event as a console message. Some machines may not sustain the max turbo frequency in all conditions and can be throttled frequently. This can lead to the flooding of console with throttle messages. So this patchset aims to redesign the presentation of this event via sysfs counters and tracepoints. Patches [2] to [4] will add a perf trace point "power:powernv_throttle" and sysfs throttle counter stats in /sys/devices/system/cpu/cpufreq/chipN. Patch [1] solves a bug in powernv_cpufreq_throttle_check(), which calls in to cpu_to_chip_id() in hot path which reads DT every time to find the chip id. Changes from v3: - Add a fix to replace cpu_to_chip_id() with simpler PIR shift to obtain the chip id. - Break patch2 in to two patches separating the tracepoint and sysfs attribute changes. Changes from v2: - Fixed kbuild test warning. drivers/cpufreq/powernv-cpufreq.c:609:2: warning: ignoring return value of 'kstrtoint', declared with attribute warn_unused_result [-Wunused-result] Shilpasri G Bhat (4): cpufreq: powernv: Remove cpu_to_chip_id() from hot-path cpufreq: powernv/tracing: Add powernv_throttle tracepoint cpufreq: powernv: Add a trace print for the throttle event cpufreq: powernv: Add sysfs attributes to show throttle stats drivers/cpufreq/powernv-cpufreq.c | 279 +++++++++++++++++++++++++++++++------- include/trace/events/power.h | 22 +++ kernel/trace/power-traces.c | 1 + 3 files changed, 250 insertions(+), 52 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html