Messages in this thread |  | | Date | Mon, 3 Oct 2016 21:38:10 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v21 15/19] perf, tools: Add README for info on parsing JSON/map files |
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Em Thu, Sep 15, 2016 at 03:24:52PM -0700, Sukadev Bhattiprolu escreveu: > Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> > Acked-by: Jiri Olsa <jolsa@redhat.com> > Acked-by: Ingo Molnar <mingo@kernel.org> > --- > Changelog[v21] > - Update README to reflect the Topics.json directory tree layout.
Fixed this:
[acme@jouet linux]$ am /wb/1.patch Applying: perf, tools: Add README for info on parsing JSON/map files .git/rebase-apply/patch:162: new blank line at EOF. + warning: 1 line adds whitespace errors. tools/perf/pmu-events/README:148: new blank line at EOF. [acme@jouet linux]$
> --- > tools/perf/pmu-events/README | 148 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 148 insertions(+) > create mode 100644 tools/perf/pmu-events/README > > diff --git a/tools/perf/pmu-events/README b/tools/perf/pmu-events/README > new file mode 100644 > index 0000000..c5ee208e > --- /dev/null > +++ b/tools/perf/pmu-events/README > @@ -0,0 +1,148 @@ > + > +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'. > + > -- > 1.8.3.1
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