LIKWID - Like I Knew What I Am Doing

Introduction

This is an effort to develop easy to use but yet powerful performance tools for the GNU Linux operating system. While the focus of LIKWID is on x86 processors some of the tools are portable and not limited to any specific architecture. LIKWID follows the philosophy:

• Simple
• Efficient
• Portable
• Extensible

Build and install instructions

FAQ

LIKWID Tools

• likwid-topology : A tool to display the thread and cache topology on multicore/multisocket computers.
• likwid-pin : A tool to pin your threaded application without changing your code. Works for pthreads and OpenMP.
• likwid-perfctr : A tool to measure hardware performance counters on recent Intel and AMD processors. It can be used as wrapper application without modifying the profiled code or with a marker API to measure only parts of the code.
• likwid-powermeter : A tool for accessing RAPL counters and query Turbo mode steps on Intel processor. RAPL counters are also available in likwid-perfctr.
• likwid-setFrequencies : A tool to print and manage the clock frequency of CPU cores.
• likwid-agent : A monitoring agent for LIKWID with multiple output backends.
• likwid-memsweeper : A tool to cleanup ccNUMA domains and LLC caches to get a clean environment for benchmarks.
• likwid-bench : A benchmarking framework for streaming benchmark kernels written in assembly.
• likwid-genTopoCfg : A config file writer that gets system topology and writes them to file for faster LIKWID startup.
• likwid-features : A tool to toggle the prefetchers and print available CPU features.

Wrapper scripts using the basic likwid tools:

• likwid-mpirun : A wrapper script enabling simple and flexible pinning of MPI and MPI/threaded hybrid applications. With integrated likwid-perfctr support.
• likwid-perfscope : A frontend application for the timeline mode of likwid-perfctr that performs live plotting using gnuplot.

LIKWID requires in most environments some daemon application to perform its operations with higher priviledges:

• likwid-accessD : Daemon to perform MSR and PCI read/write operations with higher priviledges.
• likwid-setFreq : Daemon to set the CPU frequencies with higher priviledges.

Optionally, a global configuration file likwid.cfg can be given to modify some basic run time parameters of LIKWID.

LIKWID Library

C/C++ Interface

• Marker API module
• Access module
• Config file module
• CPU information module
• NUMA memory topology module
• Thread affinity module
• CPU string parser module
• Performance monitoring module
• Power and Energy monitoring module
• Thermal monitoring module
• Time measurement module
• Memory sweeping module
• Retrieval and manipulation of processor features
• Retrieval and manipulation of processor clock frequencies

Lua Interface

• Information about LIKWID's Lua API
• Input and output functions module
• Config file module
• Access client module
• CPU information module
• NUMA memory topology module
• Thread affinity module
• Performance monitoring module
• Power and Energy monitoring module
• Thermal monitoring module
• Time measurement module
• Memory sweeping module
• Module to read and manipulate CPU features
• CPU frequency manipulation module
• Miscellaneous functions module (Some functionality not provided by Lua natively)

Fortran90 Interface

• Likwid Fortran90 Module

Supported Architectures

Intel®

• Intel® Pentium M
• Intel® Core2
• Intel® Atom
• Intel® Nehalem
• Intel® Nehalem EX
• Intel® Westmere
• Intel® Westmere EX
• Intel® Xeon Phi
• Intel® Silvermont/Airmont
• Intel® SandyBridge
• Intel® SandyBridge EP/EN
• Intel® IvyBridge
• Intel® IvyBridge EP/EN/EX
• Intel® Haswell
• Intel® Haswell EP/EN/EX
• Intel® Broadwell
• Intel® Broadwell D
• Intel® Broadwell EP/EN/EX
• Intel® Skylake
• Intel® Skylake SP
• Intel® Xeon Phi (Knights Landing)
• Intel® Xeon Phi (Knights Mill)

AMD®

• AMD® K8
• AMD® K10
• AMD® Interlagos
• AMD® Kabini
• AMD® Zen

Example Codes

Using the Likwid API:

• LIKWID API in a C/C++ application
• LIKWID API in a Lua application

Using the Marker API:

• Marker API in a C/C++ application
• Marker API in a Fortran90 application

If you have problems with LIKWID:
GitHub: https://github.com/RRZE-HPC/likwid
Bugs: https://github.com/RRZE-HPC/likwid/issues
Mailinglist: http://groups.google.com/group/likwid-users
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