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![]() Some POWER PMU event names have multiple/alternate event codes. These alternate event codes were listed in the POWER9 JSON files for reference. But the perf tool does not seem to handle duplicates cleanly. 'perf list' shows such duplicate events only once, but 'perf stat' ends up counting the first event code twice, multiplexing if necessary and we end up with double the event counts. Remove the duplicate event codes from the JSON files for now. Reported-by: Michael Petlan <mpetlan@redhat.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Anton Blanchard <anton@au1.ibm.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Link: http://lkml.kernel.org/r/20170830231506.GB20351@us.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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.. | ||
arch | ||
Build | ||
jevents.c | ||
jevents.h | ||
jsmn.c | ||
jsmn.h | ||
json.c | ||
json.h | ||
pmu-events.h | ||
README |
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. 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'.