Re: [PATCH v5 0/9] "Task_isolation" mode

Pavel Machek
2020-12-05T20:41:43Z

[-- Attachment #1: Type: text/plain, Size: 1255 bytes --]

Hi!

> General description
>
> This is the result of development and maintenance of task isolation
> functionality that originally started based on task isolation patch
> v15 and was later updated to include v16. It provided predictable
> environment for userspace tasks running on arm64 processors alongside
> with full-featured Linux environment. It is intended to provide
> reliable interruption-free environment from the point when a userspace
> task enters isolation and until the moment it leaves isolation or
> receives a signal intentionally sent to it, and was successfully used
> for this purpose. While CPU isolation with nohz provides an
> environment that is close to this requirement, the remaining IPIs and
> other disturbances keep it from being usable for tasks that require
> complete predictability of CPU timing.

So... what kind of guarantees does this aim to provide / what tasks it
is useful for?

For real time response, we have other approaches.

If you want to guarantee performnace of the "isolated" task... I don't
see how that works. Other tasks on the system still compete for DRAM
bandwidth, caches, etc...

So... what is the usecase?
Pavel
--
http://www.livejournal.com/~pavelmachek

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]