|
|
|
# Environment variables used by the LIKWID library
|
|
|
|
|
|
|
|
Some functionality of the LIKWID library can be changed by setting environment variables. Here is a list of variables used by LIKWID:
|
|
|
|
* `LIKWID_FORCE`: Enables the overwriting of counters that are detected to be in-use. The environment variable is similar to the `-f`/`--force` command line switch for `likwid-perfctr`
|
|
|
|
* `LIKWID_NO_ACCESS`: The execution does not require the access layer (access to hardware counters). For example, this variable is set by `likwid-topology` or `likwid-pin`
|
|
|
|
* `LIKWID_SILENT`: Disable stdout output caused by the library and the scripts. Some scripts provide the `-q`/`--quiet` command line switch which provides the same functionality
|
|
|
|
* `LIKWID_SKIP`: Variable content must be a hexmask. This hexmask describes which threads should be skipped while pinning. This function is required to avoid pinning the shepherd threads used by some OpenMP and MPI implementations. The version 4.3.1 introduced an automatic detection of the shepherd threads. In most cases the detection works, but if not, the hexmask overwrites the automatic detection.
|
|
|
|
* `LIKWID_DEBUG`: Verbosity settings for the LIKWID library
|
|
|
|
|
|
|
|
## Environment variables used by the MarkerAPI
|
|
|
|
* `LIKWID_FILEPATH`: Filepath for the result file of the MarkerAPI.
|
|
|
|
* `LIKWID_MODE`: Access mode for MarkerAPI
|
|
|
|
* `LIKWID_DEBUG`: Verbosity settings for the LIKWID library
|
|
|
|
* `LIKWID_EVENTS`: Event string or performance group name. Multiple event strings or performance group names can be separated by `|`
|
|
|
|
* `LIKWID_THREADS`: The CPUs LIKWID is configured to run on (comma-separated list)
|
|
|
|
* `LIKWID_PIN`: The comma-separated list contains the CPUs the application threads should be pinned to. Careful, the first CPU in the cpuset must be the last entry because the application is pinned to this CPU per default.
|
|
|
|
|
|
|
|
|
|
|
|
## Environment variables used by the LIKWID library which access mode `perf_event`
|
|
|
|
* `LIKWID_PERF_EXECPID`: The variable causes that the PID of the wrapped executable is submitted to `perf_event_open`. Consequently, only this process (and its children) are measured through `perf_event`
|
|
|
|
* `LIKWID_PERF_PID`: If you want to measure an already running process, you can put the PID in this variable and LIKWID attaches to the process
|
|
|
|
* `LIKWID_PERF_FLAGS`: The `perf_event_open` system call accepts further flags. LIKWID itself does not set any flags, but if the user wants to, the flags can be put in this variable
|
|
|
|
|
|
|
|
## Environment variables used by `likwid-mpirun`
|
|
|
|
* `LIKWID_MPI_CONNECT`: Connection method for Intel MPI. Default is `ssh`, see option `-r` of `mpdboot` or similar |
