Grégoire, thanks for your reply. This is super helpful to make a
stronger case around the affinity benefits.
Would you be able to offer additional details that you mentioned? I am
definitely interested.
Is your isolator source code publicly available?


On Tue, Jul 7, 2020 at 3:14 AM Grégoire Seux <> wrote:

> Hello,
> I'd like to give you a return of experience because we've worked on this
> last year.
> We've used CFS bandwidth isolation for several years and encountered many
> issues (lack of predictability, bugs present in old linux kernels and lack
> of cache/memory locality). At some point, we've implemented a custom
> isolator to manage cpusets (using
> as a base to write an
> isolator in a scripting language).
> The isolator had a very simple behavior: upon new task, look at which cpus
> are not within a cpuset cgroup, select (if possible) cpus from the same
> numa node and create cpuset cgroup for the starting task.
> In practice, it provided a general decrease of cpu consumption (up to 8%
> of some cpu intensive applications) and better ability to reason about the
> cpu isolation model.
> The allocation is optimistic: it tries to use cpus from the same numa node
> but if it's not possible, task is spread accross nodes. In practice it
> happens very rarely because of one small optimization to assign cpus from
> the most loaded numa node (decreasing fragmentation of available cpus
> accross numa nodes).
> I'd be glad to give more details if you are interested
> --
> Grégoire

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