Messages in this thread | | | Subject | Re: [PATCH 2/6] sched: tagging interface for core scheduling | From | Chris Hyser <> | Date | Mon, 22 Mar 2021 14:35:46 -0400 |
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On 3/22/21 2:33 PM, Peter Zijlstra wrote: > On Mon, Mar 22, 2021 at 01:57:48PM -0400, Chris Hyser wrote: >> On 3/20/21 11:46 AM, Peter Zijlstra wrote: >>> On Fri, Mar 19, 2021 at 04:32:49PM -0400, Joel Fernandes (Google) wrote: >>>> From: Josh Don <joshdon@google.com> >>>> >>>> Adds per-task and per-cgroup interfaces for specifying which tasks can >>>> co-execute on adjacent SMT hyperthreads via core scheduling. >>>> >>>> The per-task interface hooks are implemented here, but are not currently >>>> used. The following patch adds a prctl interface which then takes >>>> advantage of these. >>>> >>>> The cgroup interface can be used to toggle a unique cookie value for all >>>> descendent tasks, preventing these tasks from sharing with any others. >>>> See Documentation/admin-guide/hw-vuln/core-scheduling.rst for a full >>>> rundown. >>>> >>>> One important property of this interface is that neither the per-task >>>> nor the per-cgroup setting overrides the other. For example, if two >>>> tasks are in different cgroups, and one or both of the cgroups is tagged >>>> using the per-cgroup interface, then these tasks cannot share, even if >>>> they use the per-task interface to attempt to share with one another. >>>> >>>> The above is implemented by making the overall core scheduling cookie a >>>> compound structure, containing both a task-level cookie and a >>>> group-level cookie. Two tasks will only be allowed to share if all >>>> fields of their respective cookies match. >>>> >>>> Core scheduler has extra overhead. Enable it only for machines with >>>> more than one SMT hardware thread. >>> >>> Oh man.. I'd soooo hoped to first see the simple task interface and then >>> see the cgroup patch on top of that... I'll see if I can flip them >>> myself (on monday). >> >> Peter, given we need to rebase this and we have some cleanup, we can go >> ahead and flip the order if you have not yet done so yet. > > I didn't get around to it yet :/ So yes, please! Also can you then split > the selftest thingies?
Will do.
-chrish
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