Messages in this thread | | | From | 王擎 <> | Subject | [PATCH V2] arm64: add SCHED_CLUSTER's dependency on ACPI | Date | Tue, 26 Apr 2022 06:52:34 +0000 |
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>> >> >> >> >> >> From: Wang Qing <wangqing@vivo.com> >> >> >> >> >> >> cluster sched_domain configured by cpu_topology[].cluster_sibling, >> >> >> which is set by cluster_id, cluster_id can only get from ACPI. >> >> >> >> >> >> If the system does not enable ACPI, cluster_id is always -1, even enable >> >> >> SCHED_CLUSTER is invalid, this is misleading. >> >> >> >> >> >> So we add SCHED_CLUSTER's dependency on ACPI here. >> >> >> >> >> > >> >> >Any reason why this can't be extended to support DT based systems via >> >> >cpu-map in the device tree. IMO we almost have everything w.r.t topology >> >> >in DT and no reason to deviate this feature between ACPI and DT. >> >> > >> >> That's the problem, we parse out "cluster" info according to the >> >> description in cpu-map, but do assign it to package_id, which used to >> >> configure the MC sched domain, not cluster sched domain. >> >> >> > >> >Right, we haven't updated the code after updating the bindings to match >> >ACPI sockets which are the physical package boundaries. Clusters are not >> >the physical boundaries and the current topology code is not 100% aligned >> >with the bindings after Commit 849b384f92bc ("Documentation: DT: arm: add >> >support for sockets defining package boundaries") >> >> I see, but this commit is a long time ago, why hasn't it been used widely. >> Maybe I can help about it if you need. >> > >I assume no one cared or had a requirement for the same.
It took me a while to find the root cause why enabling SCHED_CLUSTER didn't work.
We should add SCHED_CLUSTER's dependency before implementation. Otherwise, everyone who doesn't have ACPI but use SCHED_CLUSTER will have this problem.
Thanks, Qing
> >-- >Regards, >Sudeep
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