switchtest¶
Name¶
switchtest - Xenomai context switch test
Synopsis¶
switchtest [options] threadspec threadspec...
Description¶
switchtest is part of Xenomai. It can be used to test thread context switches. switchtest creates threads of various types and attempts to switch context between these threads, printing the count of context switches every second. A suitable Xenomai enabled kernel with the respective module (xeno_posix) must be installed.
Documentation¶
switchtest - Xenomai context switch test
Options¶
Each threadspec specifies the characteristics of a thread to be created:
threadspec = (rtk|rtup|rtus|rtuo)(_fp|_ufpp|_ufps)*[0-9]*
| Thread Specification | Description |
|---|---|
| rtk | Kernel-space real-time thread |
| rtup | User-space real-time thread running in primary mode |
| rtus | User-space real-time thread running in secondary mode |
| rtuo | User-space real-time thread oscillating between modes |
| _fp | Thread with XNFPU bit armed (valid for rtk only) |
| _ufpp | Thread using FPU in primary mode (invalid for rtus) |
| _ufps | Thread using FPU in secondary mode (invalid for rtk, rtup) |
| [0-9] | CPU ID where the thread will run (0 if unspecified) |
Passing no threadspec is equivalent to running:
switchtest rtkN rtkN rtk_fpN rtk_fpN rtk_fp_ufppN rtk_fp_ufppN rtupN rtupN rtup_ufppN rtup_ufppN rtusN rtusN rtus_ufpsN rtus_ufpsN rtuoN rtuoN rtuo_ufppN rtuo_ufppN rtuo_ufpsN rtuo_ufpsN rtuo_ufpp_ufpsN rtuo_ufpp_ufpsN
with N=1,...,nr_cpus, i.e. occurrences of all the arguments for each CPU
Passing only the --nofpu or -n argument is equivalent to running:
switchtest rtkN rtkN rtupN rtupN rtusN rtusN rtuoN rtuoN
similar to the above.
switchtest accepts the following options:
| Option | Description |
|---|---|
| --help, -h | Print usage information and exit |
| --lines |
Print headers every |
| --quiet, -q | Prevent the program from printing context switch count every second |
| --timeout |
Limit the test duration to |
| --nofpu, -n | Disable any use of FPU instructions |
switchtest was written by Philippe Gerum and Gilles Chanteperdrix. This man page was written by Roland Stigge.
Map¶
| Output | Description |
|---|---|
| RTT | Real-Time Tick, shows the time at which the measurement was taken. |
| RTH | Real-Time Histogram, shows the distribution of latency values. |
| RTD | Real-Time Data, shows the actual latency measurements. |
| RTS | Real-Time Statistics, shows the overall statistics after the test is complete. |