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Intel PMU profiling tools

Project README

pmu-tools

Python linting and testing jevents test

pmu tools is a collection of tools and libraries for profile collection and performance analysis on Intel CPUs on top of Linux perf. This uses performance counters in the CPU.

Quick (non-) installation

pmu-tools doesn't really need to be installed. It's enough to clone the repository and run the respective tool (like toplev or ocperf) out of the source directory.

To run it from other directories you can use export PATH=$PATH:/path/to/pmu-tools or symlink the tool you're interested in to /usr/local/bin or ~/bin. The tools automatically find their python dependencies.

When first run, toplev / ocperf will automatically download the Intel event lists from https://github.com/intel/perfmon. This requires working internet access. Later runs can be done offline. It's also possible to download the event lists ahead, see pmu-tools offline

toplev works with both python 2.7 and python 3. However it requires an not too old perf tools and depending on the CPU an uptodate kernel. For more details see toplev kernel support

The majority of the tools also don't require any python dependencies and run in "included batteries only" mode. The main exception is generating plots or XLSX spreadsheets, which require external libraries.

If you want to use those run

  pip install -r requirements.txt

once, or follow the command suggested in error messages.

jevents is a C library. It has no dependencies other than gcc/make and can be built with

cd jevents
make

Quick examples

toplev -l2 program

measure whole system in level 2 while program is running

toplev -l1 --single-thread program

measure single threaded program. On hyper threaded systems with Skylake or older the system should be idle.

toplev -NB program

Measure program showing consolidated bottleneck view and extra information associated with bottlenecks. Note this will multiplex performance counters, so there may be measuring errors.

toplev -NB --run-sample program

Measure programing showing bottlenecks and extra nodes, and automatically sample for the location of bottlenecks in a second pass.

toplev --drilldown --only-bottleneck program

Rerun workload with minimal multiplexing until critical bottleneck is found. Only print critical bottleneck

toplev -l3 --no-desc -I 100 -x, sleep X

measure whole system for X seconds every 100ms, outputting in CSV format.

toplev --all --core C0 taskset -c 0,1 program

Measure program running on core 0 with all nodes and metrics enabled.

toplev --all --xlsx x.xlsx -a sleep 10

Generate spreadsheet with full system measurement for 10 seconds

For more details on toplev please see the toplev tutorial

What tool to use for what?

You want to:

  • understand CPU bottlenecks on the high-level: use toplev.
  • display toplev output graphically: toplev --xlsx (or --graph)
  • know what CPU events to run, but want to use symbolic names for a new CPU: use ocperf.
  • measure interconnect/caches/memory/power management on Xeon E5+: use ucevent (or toplev)
  • Use perf events from a C program: use jevents
  • Query CPU topology or disable HyperThreading: use cputop
  • Change Model Specific Registers: use msr
  • Change PCI config space: use pci

For more details on the tools see TOOLS

All features:

Major tools/libraries

  • The "ocperf" wrapper to "perf" that provides a full core performance counter event list for common Intel CPUs. This allows to use all the Intel events, not just the builtin events of perf. Can be also used as a library from other python programs
  • The "toplev.py" tool to identify the micro-architectural bottleneck for a workload. This implements the TopDown or TopDown2 methodology.
  • The "ucevent" tool to manage and compute uncore performance events. Uncore is the part of the CPU that is not core. Supports many metrics for power management, IO, QPI (interconnect), caches, and others. ucevent automatically generates event descriptions for the perf uncore driver and pretty prints the output. It also supports computing higher level metrics derived from multiple events.
  • A library to resolve named intel events (like INST_RETIRED.ANY) to perf_event_attr (jevents) and provide higher level function for using the Linux perf API for self profiling or profiling other programs. It also has a "perf stat" clone called "jestat"
  • A variety of tools for plotting and post processing perf stat -I1000 -x, or toplev.py -I1000 -x, interval measurements.
  • Some utility libraries and functions for MSR access, CPU topology and other functionality,as well as example programs how to program the Intel PMU.

There are some obsolete tools which are not supported anymore, like simple-pebs. These are kept as PMU programming reference, but may need some updates to build on newer Linux kernels.

Recent new features:

  • toplev now supports Meteor Lake systems.
  • Add a new genretlat.py tool to tune the toplev model for a workload. The basic tuning needs to be generated before first toplev use using genretlat -o mtl-retlat.json ./workloads/BC1s (or suitable workload). toplev has a new --ret-latency option to override the tuning file.

TMA 4.7 release

  • toplev updated to TMA 4.7:

    • New --hbm-only for sprmax in HBM Only mode. toplev currently cannot auto detect this condition.
    • New Models
      • SPR-HBM: model for Intel Xeon Max (server) processor covering HBM-only mode (on top of cache mode introduced in 4.6 release)
    • New Features
      • Releasing the Bottlenecks View - a rather complete version [SKL onwards]
        • Bottlenecks View is An abstraction or summarization of the 100+ TMA tree nodes into a 12-entry vector of familiar performance issues, presented under the Info.Bottlenecks section.
      • This release introduces Core_Bound_Est metric: An estimation of total pipeline cost when the execution is compute-bound.
      • Besides, balanced distrubtion among Branching Retired, Irregular_Overhead, Mispredictions and Instruction_Fetch_BW as well as
      • enhanced Cache_Memory_Latency to account for Stores info better accuracy.
    • New Tree Metrics (nodes)
      • HBM_Bound: stalls due to High Bandwidth Memory (HBM) accesses by loads.
    • Informative Metrics
    • New: Uncore_Frequency in server models
    • New: IpPause [CFL onwards]
    • Key Enhancements & fixes
      • Hoisted Serializing_Operation and AMX_Busy to level 3; directly under Core Bound [SKL onwards]
      • Swapped semantics of ILP (becomes per-thread) and Execute (per physical core) info metrics
      • Moved Nop_Instructions to Level 4 under Other_Light_Op [SKL onwards]
      • Moved Shuffles_256b to Level 4 under Other_Light_Op [ADL onwards]
      • Renamed Local/Remote_DRAM to Local/Remote_MEM to account for HBM too
      • Reduced # events when SMT is off [all]
      • Reduced # events for HBM metrics; fixed MEM_Bandwidth/Latency descriptions [SPR-HBM]
      • Tuned Threshold for: Branching_Overhead; Fetch_Bandwidth, Ports_Utilized_3m
  • toplev has new options:

    • --node-metrics or -N collects and shows metrics related to selected TMA nodes if their nodes cross the threshold. With --drilldown it will show only the metrics of the bottleneck.
    • --areas can select nodes and metrics by area
    • --bottlenecks or -B shows the bottleneck view metrics (equivalent to --areas Info.Bottleneck)
    • --only-bottleneck only shows the bottleneck, as well as its associated metrics if enabled.
  • interval-plot has --level and --metrics arguments to configure the inputs. It now defaults to level 1 only, no metrics to make the plots more readable.

  • toplev has a new --reserved-counters option to handle systems that reserve some generic counters.

  • toplev has a new --no-sort option to disable grouping metrics with tree nodes.

TMA 4.6 release

  • toplev updated to Ahmad Yasin's TMA 4.6
    • Support for Intel Xeon Max processors (SPRHBM)
    • New Features:
      • Support for optimized power-performance states via C01/C02_Wait nodes under Core Bound category as well as C0_Wait info metric [ADL onwards]
      • HBM_Bound: stalls due to High Bandwidth Memory (HBM) accesses by loads.
      • C01/C02_Wait: cycles spent in C0.1/C0.2 power-performance optimized states
      • Other_Mispredicts: slots wasted due to other cases of misprediction (non-retired x86 branches or other types)
      • Other_Nukes: slots wasted due to Nukes (Machine Clears) not related to memory ordering.
      • Info.Bottlenecks: Memory_Synchronization, Irregular_Overhead (fixes Instruction_Fetch_BW), Other_Bottlenecks [SKL onwards]
      • CPUs_Utilized - Average number of utilized CPUs [all]
      • New metrics UC_Load_PKI, L3/DRAM_Bound_L, Spec_Clears_Ratio, EPC [SKL onwards]
      • Unknown_Branch_Cost and Uncore_Rejects & Bus_Lock_PKI (support for Resizable Bar) [ADL]
      • Enabled FP_Vector_128b/256b nodes in SNB/JKT/IVB/IVT
      • Enabled FP_Assists, IpAssist into, as well as Fixed Mixing_Vectors [SKL through TGL]
      • TIOPs plus 8 new metrics Offcore_PKI and R2C_BW [SPR, SPR-HBM]
      • Grouped all Uncore-based Mem Info metric under MemOffcore distinct group (to ease skipping their overhead) [all]
    • Key Enhancements & fixes
      • Reduced # events (multiplexing) for GFLOPs, FLOPc, IpFLOP, FP_Scalar and FP_Vector [BDW onwards]
      • Reduced # events (multiplexing) & Fixed Serializing_Operations, Ports_Utilized_0 [ADL onwards]
      • Fixed Branch_Misprediction_Cost overestimate, Mispredictions [SKL onwards]
      • Fixed undercount in FP_Vector/IpArith (induced by 4.5 update) + Enabled/fixed IO_Read/Write_BW [SPR]
      • Tuned #Avg_Assist_Cost [SKL onwards]
      • Remove X87_Use [HSW/HSX]
      • Renamed Shuffles node & some metrics/groups in Info.Bottlenecks and Info.Memory*. CountDomain fixes

TMA 4.4 release

  • toplev updated to Ahmad Yasin's TMA 4.4

    • Add support for Sapphire Rapids servers
      • New breakdown of Heavy_Operations, add new nodes for Assists, Page Faults
      • A new Int_Operations level 3 node, including Integer Vector and Shuffle
      • Support for RDT MBA stalls.
      • AMX and FP16 support
      • Better FP_Vector breakdown
      • Support 4wide MITE breakdown.
      • Add new Info.Pipeline Metrics group.
      • Support for Retired/Executed uops and String instruction cycles
      • Frequency of microcode assits.
      • Add Core_Bound_Likely for SMT and IpSWF for software prefetches.
      • Cache bandwidth is split per processor and per core.
      • Snoop Metric group for cross processor snoops.
      • Various bug fixes and improvements.
  • Support for running on Alderlake with a hybrid Goldencove / Gracemont model Add a new --aux option to control the auxillary nodes on Atom. --cputype atom/core is supported to filter on core types.

  • cputop supports an atom/core shortcut to generate the cpu mask of hybrid CPUs. Use like toplev $(cputop core cpuset) workload

  • toplev now supports a --abbrev option to abbreviate node names

  • Add experimental --thread option to support per SMT thread measurements on pre ICL CPUs.

TMA 4.3 release

  • toplev updated to Ahmad Yasin's TMA 4.3: New Retiring.Light_Operations breakdown

    Notes: ADL is missing so far. TGL/RKL still use the ICL model. if you see missing events please remove ~/.cache/pmu-events/* to force a redownload

    • New Tree Metrics (nodes)
      • A brand new breakdown of the Light_Operations sub-category (under Retiring category) per operation type:
        • Memory_Operations for (fraction of retired) slots utilized by load or store memory accesses
        • Fused_Instructions for slots utilized by fused instruction pairs (mostly conditional branches)
        • Non_Fused_Branches for slots utilized by remaining types of branches.
        • (Branch_Instructions is used in lieu of the last two nodes for ICL .. TGL models)
        • Nop_Instructions for slots utilized by NOP instructions
        • FP_Arith - a fraction estimate of arithmetic floating-point operations (legacy)
      • CISC new tree node for complex instructions (under the Heavy_Operations sub-category)
      • Decoder0_Alone new tree node for instructions requiring heavy decoder (under the Fetch_Bandwidth sub-category)
      • Memory_Fence new tree node for LFENCE stalls (under the Core_Bound sub-category)
    • Informative Groups
      • New Info.Branches group for branch instructions of certain types: Cond_TK (Conditional TaKen branches), Cond_NT (Conditional Non-Taken), CallRet, Jump and Other_Branches.
      • Organized (almost all) Info metrics in 5 mega-buckets of {Fed, Bad, Ret, Cor, Mem} using the Metric Group column
    • New Informative Metrics
      • UpTB for Uops per Taken Branch
      • Slots_Utilization for Fraction of Physical Core issue-slots utilized by this Logical Processor [ICL onwards]
      • Execute_per_Issue for the ratio of Uops Executed to Uops Issued (allocated)
      • Fetch_UpC for average number of fetched uops when the front-end is delivering uops
      • DSB_Misses_Cost for Total penalty related to DSB misses
      • IpDSB_Miss_Ret for Instructions per (any) retired DSB miss
      • Kernel CPI for Cycles Per Instruction in kernel (operating system) mode
    • Key Enhancements & fixes
      • Fixed Heavy_Operations for few uop instructions [ICL, ICX, TGL].
      • Fixed Fetch_Latency overcount (or Fetch_Bandwidth undercount) [ICL, ICX, TGL]
      • Capped nodes using fixed-costs, e.g. DRAM_Bound, to 100% max. Some tools did this in ad-hoc manner thus far [All]
      • Fixed DTLB_{Load,Store} and STLB_Hit_{Load,Store} in case of multiple hits per cycles [SKL onwards]
      • Fixed Lock_Latency to account for lock that hit in L1D or L2 caches [SKL onwards]
      • Fixed Mixing_Vectors and X87_Use to Clocks and Slots Count Domains, respectively [SKL onwards]
      • Many other fixes: Thresholds, Tagging (e.g. Ports_Utilized_2), Locate-with, Count Domain, Metric Group, Metric Max, etc
  • jestat now supports CSV output (-x,), not aggregated.

  • libjevents has utility functions to output event list in perf stat style (both CSV and normal)

  • toplev now outputs multiplexing statistics by default. This can be disabled with --no-mux.

  • cputop now supports hybrid types (type=="core"/"atom")

  • ucevent now supports Icelake Server

  • toplev now supports Icelake Server

TMA 4.2 release

  • toplev updated to Ahmad Yasin's TMA 4.2: Bottlenecks Info group, Tuned memory access costs
    • New Metrics
      • New Info.Bottlenecks group aggregating total performance-issue costs in SLOTS across the tree: [SKL onwards]
        • Memory_Latency, Memory_Bandwidth, Memory_Data_TLBs
        • Big_Code, Instruction_Fetch_BW, Branching_Overheads and
        • Mispredictions (introduced in 4.1 release)
      • New tree node for Streaming_Stores [ICL onwards]
    • Key Enhancements & fixes
      • Tuned memory metrics with up-to-date frequency-based measured costs [TGL, ICX]
        • The Average_Frequency is calculated using the TSC (TimeStamp Counter) value
        • With this key enhancement #Mem costs become NanoSecond- (was Constant), DurationTimeInMilliSeconds becomes ExternalParameter CountDomain and #Base_Frequency is deprecated
        • The previous method of setting frequency using Base_Frequency is deprecated.
      • Fixed Ports_Utilization for detection of serializing operations - issue#339 [SKL onwards]
      • Tuned MITE, DSB, LSD and move to Slots_Estimated domain [all]
      • Capping DTLB_Load and STLB_Hit_Load cost using events in Clocks CountDomain [SKL onwards]
      • Tuned Pause latency using default setting [CLX]
      • Fixed average Assists cost [IVB onwards]
      • Fixed Mispredicts_Resteers Clears_Resteers Branch_Mispredicts Machine_Clears and Mispredictions [ICL+]
      • A parameter to avoid using PERF_METRICS MSR e.g. for older OS kernels (implies higher event multiplexing)
      • Reduced # events for select nodes collections (lesser event multiplexing): Backend_Bound/Core_Bound, Clear_Resteers/Unknwon_Branches, Kernel_Utilization
      • Other fixes: Thresholds, Tagging (e.g. Ports_Utilized_2), Locate-with, etc
  • toplev now has a --parallel argument to can process large --import input files with multiple threads. There is a new interval-merge tool that can merge multiple perf-output files.
  • toplev now supports a --subset argument that can process parts of --import input files, either by splitting them or by sampling. This is a building block for more efficient processing of large input files.
  • toplev can now generate scripts to collect data with perf stat record to lower runtime collection overhead, and import the perf.data, using a new --script-record option. This currently requires unreleased perf patches, hopefully in Linux 5.11.
  • toplev can now support json files for Chrome's about://tracing with --json
  • toplev now supports --no-multiplex in interval mode (-Ixxx)
  • The tools now don't force python 2 anymore to support running out of the box on distributions which do not install python 2.
  • toplev now hides the perf command line by default. Override with --perf.
  • Updated to TMA 4.11: Fixed an error in misprediction-related and Power License metrics
  • toplev now supports the new fixed TMA metrics counters on Icelake. This requires the upcoming 5.9+ kernel.

TMA 4.1 release

  • toplev was updated to Ahmad Yasin's/Anton Hanna's TMA 4.1 New Metrics:
    • Re-arrange Retiring Level 2 into Light_Operations & Heavy_Operations. Light_Operations replaces the previous Base (or "General Retirement") while Heavy_Operations is a superset of the Microcode_Sequencer node (that moves to Level 3)
    • Mixing_Vectors: hints on a pitfall when intermixing the newer AVX* with legacy SSE* vectors, a tree node under Core Bound [SKL onwards] Key Enhancements & fixes
    • Tuning of Level 2 breakdown for Backend_Bound, Frontend_Bound (rollback FRONTEND_RETIRED 2-events use) [SKL onwards]
    • Improved branch misprediction related metrics to leverage a new PerfMon event [ICL onwards]
    • Improved CORE_CLKS & #Retire_Slots-based metrics [ICL onwards]
    • Adjusted cost of all nodes using MEM_LOAD_*RETIRED.* in case of shadow L1 d-cache misses
    • renamed Frontend_ to Fetch_Latency/Bandwidth [all]
    • Additional documentation/details to aid automated parsing in ‘For Tool Developers’.
    • Other fixes including Thresholds, Tagging (e.g. $issueSnoops), Locate-with, Metric Group
  • toplev can now generate charts in xlsx files with the --xchart option.

Older changes in CHANGES

Help wanted

  • The plotting tools could use a lot of improvements. Both tl-serve and tl-barplot. If you're good in python or JS plotting any help improving those would be appreciated.

Mailing list

Please post to the [email protected] mailing list. For bugs please open an issue on https://github.com/andikleen/pmu-tools/issues

Licenses

ocperf, toplev, ucevent, parser are under GPLv2, jevents is under the modified BSD license.

Andi Kleen

Open Source Agenda is not affiliated with "Pmu Tools" Project. README Source: andikleen/pmu-tools
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