This page describes recommended techniques to optimize the host operating system for real-time execution of DPsim.

In principle, real-time execution is supported on all platforms. However, we recommend to use an optimized Linux installation.

Operating System and Kernel

For minimum latency several kernel and driver settings can be optimized.

To get started, we recommend the Redhat Real-time Tuning Guide.

A PREEMPT_RT patched Linux kernel is recommended. Precompiled kernels for Fedora can be found here:

Use the tuned tool for improving general real-time performance. Please adjust the setting isolated_cpucores according to your hardware and enable the realtime profile as follows:

  $ dnf install tuned-profiles-realtime
  $ echo "realtime" > /etc/tuned/active_profile
  $ echo "isolated_cpucores=6-7" >> /etc/tuned/realtime-variables.conf
  $ systemctl enable tuned && systemctl start tuned
  $ systemctl reboot

Running a real-time simulation

As a reference, real-time simulation examples are provided in the Examples/Cxx folder of the DPsim repository.

In order to run a real-time simulation, the simulation process must be started in a special way in order to change the execution priority, scheduler and CPU affinity. For this purpose the chrt and taskset commands are used. In the following example, we pin the execution of the simulation to CPU cores 6-7 which have been reserved previously by the tuned real-time profile (see above).

  $ taskset --all-tasks --cpu-list 6-7 \
  $ chrt --fifo 99 \
  $ Examples/Cxx/RT_DP_CS_R_1

More details:

Some proposals for the selection of appropriate server hardware:

  • Server-grade CPU, e.g. Intel Xeon. A multi-core system enables true parallel execution of several decoupled systems
  • Server-grade network cards, e.g. Intel PRO/1000. These allow offloading of UDP checksumming to the hardware