sel4bench

sel4bench is a benchmarking applications and support library for seL4.

To get this project, check out the project manifest.

Applications

We provide multiple applications for benchmarking different paths in the kernel.

sel4bench

This is the driver application: it launches each benchmark in a separate process and collects, processes, and outputs results.

ipc

This is a hot-cache benchmark of the IPC path.

irq

This is a hot-cache benchmark of the IRQ path, measured from inside the kernel. It requires tracepoints to be placed on the IRQ path where the meaurements are to be taken from.

irquser

This is a hot-cache benchmark of the IRQ path, measured from user space.

scheduler

This is a hot-cache benchmark of a scheduling decision. It works by using a producer/consumer pattern between two notification objects. This benchmark also measures seL4_Yield().

signal

This is a hot-cache benchmark of the signal path in the kernel, measured from user space.

smp

This is an intra-core IPC round-trip benchmark to check overhead of kernel synchronization on IPC throughput.

vcpu (AArch64 only)

This benchmark will execute a thread as a VCPU (an EL1 guest kernel) and then obtain numbers for the following actions:

• Privilege escalation from EL1 to EL2 using the HVC instruction.
• Privilege de-escalation from EL2 to EL1 using the ERET instruction.
• The cost of a null invocation of the EL2 kernel using HVC.
• The cost of an seL4_Call() from an EL1 guest thread to a native seL4 thread.
• The cost of an seL4_Reply() from an seL4 native thread to an EL1 guest thread.

Note: In order to run this benchmark, you must notify the build system that you wish to enable this benchmark by passing -DVCPU=true on the command line, which will cause the kernel to be compiled to run in EL2. You must also ensure that you pass -DHARDWARE=false to disable the hardware tests.

Since this benchmark will cause the kernel image to be an EL2 image, it will have an impact on the observed numbers for the other benchmark applications as well, since they’ll be using an unexpected kernel build.

Adding a new benchmark

Contributing a new benchmark to seL4bench requires a few steps:

• Under apps, create a directory for your new benchmark and:
  • Provide a CMakelists.txt file that defines a new executable.
  • Provide a src folder that contains the source code for your benchmark.
• Under apps/sel4bench:
  • Update CMakeLists.txt to add your new benchmark to the list of benchmarks.
  • Under src:
    • Update benchmark.h to include your generated config for your benchmark, and provide a function declaration that will act as the entry point for your benchmark.
    • Provide a <benchmark_name>.c file that implements the above function declaration. This function should return a benchmark_t struct. Construct this struct accordingly. The struct expects a function to process the results of the benchmark, which you should provide in this file as well
    • Inside main.c, add your entry point function that was declared/defined above to the array of benchmark_t present.
• Update easy-settings.cmake to add your new benchmark. You can define here whether the benchmark should be enabled by default or not.
• Under libsel4benchsupport/include:
  • Provide a <benchmark_name.h> file that provides any extra definitions that your benchmark may need. You will also generally provide a benchmark_name_results_t struct here, which will be used to store the results of your benchmark when processing.
• Update settings.cmake to include your new benchmark.