A long term project for CPU isolation is to allow its features to be enabled and disabled through cpusets. This includes nohz_full, unbound load affinity involving kthreads, workqueues and timers, managed IRQs, RCU nocb mode, etc... These behaviors are currently fixed in stone at boot time and can't be changed until the next reboot... The purpose is to allow tuning these at runtime, which...
Changes to smp_call_function/queue_work_on style APIs
to take isolation into consideration, more specifically, would like to possibly return errors
for the callers who can handle them.
CPUs can be disturbed quite easily by RCU. This can hurt power especially on battery-powered systems, where RCU can be a major consumer of power. Different strategies can be tried to mitigate power which we will show along with power data. Also I have been working on some patches to further reduce RCU activity in frequently-called paths like file close. This presentation is to discuss some...
CPU isolation comes with a handful of cpumasks to help determine which CPUs can
sanely be interrupted, but those are not always checked when sending an IPI, nor
is it always obvious wether a given cross-call could be omitted (or delayed) if
targeting an isolated CPU.
[1] (with [2] and [3] as required foundations) shows a way to defer cross-call
work targeting isolated CPUs to the next...
The osnoise tracers enable the simulation of common HPC workload while tracing all the external sources of noise in an optimized way. This was discussed two years ago. The rtla osnoise adds an easy-to-use interface for osnoise, enabling the tracer to the masses. rtla was discussed last year. These tools now are available and in use by members of this community in their daily activities.
But...
