Messages in this thread | | | Date | Fri, 13 May 2022 10:36:26 +0200 | Subject | Re: [PATCH V2] arch_topology: support parsing cluster_id from DT | From | Dietmar Eggemann <> |
| |
On 12/05/2022 16:17, Sudeep Holla wrote: > On Wed, May 11, 2022 at 02:52:56AM -0700, Qing Wang wrote: >> From: Wang Qing <wangqing@vivo.com> >> >> Use nested cluster structures in DT to support describing multi-level >> cluster topologies and increase the parsing of nested cluster. >> >> Notice: the clusters describing in DT currently are not physical >> boundaries, since changing "cluster" to "socket" is too involved and error >> prone, this patch will not have any effect on one-level cluster topo, but >> can support the mutil-level cluster topo to support CLUSTER_SCHED. > > Sorry the socket/package_id is broken. If we are playing with cluster_id > which is now wrongly presented as package_id, you are forced to fix that > too. We don't want to break that in a different way or leave that as is > since the cluster_id and package ids now show up as same now. Earlier the > cluster_id was -1.
We can leave package_id=0 (and maybe add socket parsing later) and use llc_id instead. Like some Arm server do via ACPI. This will leave cluster_id for Armv9 L2 sharing. cluster_id is also used in servers for 2. level "clustering", e.g. Kunpeng920 L3-tags or Ampere Altra's SCU boundaries.
This way we can achieve both. (1) not use package_id for cluster and (2) have cluster_id available for 2. level cluster.
I just send out a lightly tested RFC:
https://lkml.kernel.org/r/20220513083400.343706-1-dietmar.eggemann@arm.com
> > I had a look when I started reviewing your patch. Assuming we don't need > nested cluster support yet, I have some patches(not built or tested > unfortunately yet). Let me know your thoughts. If you think you still > need support for some kind of nested cluster, build that on top of this. > Also I haven't bothered about sched domains as this purely relates to > topology and how this is mapped to sched domain is orthogonal. > > If anything is broken, that needs to be fixed separately there. I see the > idea here is correct and would like to push the patches once I build/test > and get some review/more testing.
| |