Linux Plumbers Conference 2022 is pleased to host the CPU Isolation Microconference

CPU Isolation is an ability to shield workloads with extreme latency or performance requirements from interruptions (also known as Operating System noise) provided by a close combination of several kernel and userspace components. An example of such workloads are DPDK use cases in Telco/5G where even the shortest interruption can cause packet losses, eventually leading to exceeding QoS requirements.

Despite considerable improvements in the last few years towards implementing full CPU Isolation (nohz_full, rcu_nocb, isolcpus, etc.), there are issues to be addressed, as it is still relatively simple to highlight sources of OS noise just by running synthetic workloads mimicking polling (always running) type of application similar to the ones mentioned above.

There were recent improvements and discussions about CPU isolation features on LKML, and tools such as osnoise tracer and rtla osnoise improved the CPU isolation analysis. Nevertheless, this is an ongoing process, and discussions are needed to speed up solutions for existing issues and to improve the existing tools and methods.

The purpose of CPU Isolation MC is to get together to discuss open problems, most notably: how to improve the identification of OS noise sources, how to track them publicly and how to tackle the sources of noise that have already been identified.

A non exhaustive list of potential topics is:

• OS noise profiling (format and public DB for the community)
• Tracing to detect OS noise: the rtla osnoise tracer and what it’s missing
• TLB/icache flush deferral
• Extend cpuset v2 CPU partition feature to replace isolcpus kernel command line
• rt-trace-bpf tool
• Task isolation
• smp_call_function API improvements

Please come and join us in the discussion about CPU isolation.

We hope to see you there!