The contents of this directory allow users to specify PMU events in their CPUs by their symbolic names rather than raw event codes (see example below). The main program in this directory, is the 'jevents', which is built and executed _BEFORE_ the perf binary itself is built. The 'jevents' program tries to locate and process JSON files in the directory tree tools/perf/pmu-events/arch/foo. - Regular files with '.json' extension in the name are assumed to be JSON files, each of which describes a set of PMU events. - Regular files with basename starting with 'mapfile.csv' are assumed to be a CSV file that maps a specific CPU to its set of PMU events. (see below for mapfile format) - Directories are traversed, but all other files are ignored. The PMU events supported by a CPU model are expected to grouped into topics such as Pipelining, Cache, Memory, Floating-point etc. All events for a topic should be placed in a separate JSON file - where the file name identifies the topic. Eg: "Floating-point.json". All the topic JSON files for a CPU model/family should be in a separate sub directory. Thus for the Silvermont X86 CPU: $ ls tools/perf/pmu-events/arch/x86/Silvermont_core Cache.json Memory.json Virtual-Memory.json Frontend.json Pipeline.json Using the JSON files and the mapfile, 'jevents' generates the C source file, 'pmu-events.c', which encodes the two sets of tables: - Set of 'PMU events tables' for all known CPUs in the architecture, (one table like the following, per JSON file; table name 'pme_power8' is derived from JSON file name, 'power8.json'). struct pmu_event pme_power8[] = { ... { .name = "pm_1plus_ppc_cmpl", .event = "event=0x100f2", .desc = "1 or more ppc insts finished,", }, ... } - A 'mapping table' that maps each CPU of the architecture, to its 'PMU events table' struct pmu_events_map pmu_events_map[] = { { .cpuid = "004b0000", .version = "1", .type = "core", .table = pme_power8 }, ... }; After the 'pmu-events.c' is generated, it is compiled and the resulting 'pmu-events.o' is added to 'libperf.a' which is then used to build perf. NOTES: 1. Several CPUs can support same set of events and hence use a common JSON file. Hence several entries in the pmu_events_map[] could map to a single 'PMU events table'. 2. The 'pmu-events.h' has an extern declaration for the mapping table and the generated 'pmu-events.c' defines this table. 3. _All_ known CPU tables for architecture are included in the perf binary. At run time, perf determines the actual CPU it is running on, finds the matching events table and builds aliases for those events. This allows users to specify events by their name: $ perf stat -e pm_1plus_ppc_cmpl sleep 1 where 'pm_1plus_ppc_cmpl' is a Power8 PMU event. In case of errors when processing files in the tools/perf/pmu-events/arch directory, 'jevents' tries to create an empty mapping file to allow the perf build to succeed even if the PMU event aliases cannot be used. However some errors in processing may cause the perf build to fail. Mapfile format =============== The mapfile enables multiple CPU models to share a single set of PMU events. It is required even if such mapping is 1:1. The mapfile.csv format is expected to be: Header line CPUID,Version,Dir/path/name,Type where: Comma: is the required field delimiter (i.e other fields cannot have commas within them). Comments: Lines in which the first character is either '\n' or '#' are ignored. Header line The header line is the first line in the file, which is always _IGNORED_. It can empty. CPUID: CPUID is an arch-specific char string, that can be used to identify CPU (and associate it with a set of PMU events it supports). Multiple CPUIDS can point to the same File/path/name.json. Example: CPUID == 'GenuineIntel-6-2E' (on x86). CPUID == '004b0100' (PVR value in Powerpc) Version: is the Version of the mapfile. Dir/path/name: is the pathname to the directory containing the CPU's JSON files, relative to the directory containing the mapfile.csv Type: indicates whether the events or "core" or "uncore" events. Eg: $ grep Silvermont tools/perf/pmu-events/arch/x86/mapfile.csv GenuineIntel-6-37,V13,Silvermont_core,core GenuineIntel-6-4D,V13,Silvermont_core,core GenuineIntel-6-4C,V13,Silvermont_core,core i.e the three CPU models use the JSON files (i.e PMU events) listed in the directory 'tools/perf/pmu-events/arch/x86/Silvermont_core'. on value='0' selected='selected'>unified
authorSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>2017-02-03 14:18:39 -0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-02-04 00:11:08 +0100
commit6e978b22efa1db9f6e71b24440b5f1d93e968ee3 (patch)
treec666f7a26b860674848949e39a610222b0723f89 /net/caif/Kconfig
parent3c223c19aea85d3dda1416c187915f4a30b04b1f (diff)
cpufreq: intel_pstate: Disable energy efficiency optimization
Some Kabylake desktop processors may not reach max turbo when running in HWP mode, even if running under sustained 100% utilization. This occurs when the HWP.EPP (Energy Performance Preference) is set to "balance_power" (0x80) -- the default on most systems. It occurs because the platform BIOS may erroneously enable an energy-efficiency setting -- MSR_IA32_POWER_CTL BIT-EE, which is not recommended to be enabled on this SKU. On the failing systems, this BIOS issue was not discovered when the desktop motherboard was tested with Windows, because the BIOS also neglects to provide the ACPI/CPPC table, that Windows requires to enable HWP, and so Windows runs in legacy P-state mode, where this setting has no effect. Linux' intel_pstate driver does not require ACPI/CPPC to enable HWP, and so it runs in HWP mode, exposing this incorrect BIOS configuration. There are several ways to address this problem. First, Linux can also run in legacy P-state mode on this system. As intel_pstate is how Linux enables HWP, booting with "intel_pstate=disable" will run in acpi-cpufreq/ondemand legacy p-state mode. Or second, the "performance" governor can be used with intel_pstate, which will modify HWP.EPP to 0. Or third, starting in 4.10, the /sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference attribute in can be updated from "balance_power" to "performance". Or fourth, apply this patch, which fixes the erroneous setting of MSR_IA32_POWER_CTL BIT_EE on this model, allowing the default configuration to function as designed. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Reviewed-by: Len Brown <len.brown@intel.com> Cc: 4.6+ <stable@vger.kernel.org> # 4.6+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'net/caif/Kconfig')