On Thu, Sep 15, 2022 at 08:01:18PM +0800, Yicong Yang wrote:
Hi Darren,
Hi Yicong,
...
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 1d6636ebaac5..5497c5ab7318 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -667,6 +667,15 @@ const struct cpumask *cpu_coregroup_mask(int cpu) core_mask = &cpu_topology[cpu].llc_sibling; }
- /*
* For systems with no shared cpu-side LLC but with clusters defined,* extend core_mask to cluster_siblings. The sched domain builder will* then remove MC as redundant with CLS if SCHED_CLUSTER is enabled.*/- if (IS_ENABLED(CONFIG_SCHED_CLUSTER) &&
cpumask_subset(core_mask, &cpu_topology[cpu].cluster_sibling))core_mask = &cpu_topology[cpu].cluster_sibling;- return core_mask;
}
Is this patch still necessary for Ampere after Ionela's patch [1], which will limit the cluster's span within coregroup's span.
Yes, see: https://lore.kernel.org/lkml/YshYAyEWhE4z%2FKpB@fedora/
Both patches work together to accomplish the desired sched domains for the Ampere Altra family.
I found an issue that the NUMA domains are not built on qemu with:
qemu-system-aarch64 \ -kernel ${Image} \ -smp 8 \ -cpu cortex-a72 \ -m 32G \ -object memory-backend-ram,id=node0,size=8G \ -object memory-backend-ram,id=node1,size=8G \ -object memory-backend-ram,id=node2,size=8G \ -object memory-backend-ram,id=node3,size=8G \ -numa node,memdev=node0,cpus=0-1,nodeid=0 \ -numa node,memdev=node1,cpus=2-3,nodeid=1 \ -numa node,memdev=node2,cpus=4-5,nodeid=2 \ -numa node,memdev=node3,cpus=6-7,nodeid=3 \ -numa dist,src=0,dst=1,val=12 \ -numa dist,src=0,dst=2,val=20 \ -numa dist,src=0,dst=3,val=22 \ -numa dist,src=1,dst=2,val=22 \ -numa dist,src=1,dst=3,val=24 \ -numa dist,src=2,dst=3,val=12 \ -machine virt,iommu=smmuv3 \ -net none \ -initrd ${Rootfs} \ -nographic \ -bios QEMU_EFI.fd \ -append "rdinit=/init console=ttyAMA0 earlycon=pl011,0x9000000 sched_verbose loglevel=8"
I can see the schedule domain build stops at MC level since we reach all the cpus in the system:
[ 2.141316] CPU0 attaching sched-domain(s): [ 2.142558] domain-0: span=0-7 level=MC [ 2.145364] groups: 0:{ span=0 cap=964 }, 1:{ span=1 cap=914 }, 2:{ span=2 cap=921 }, 3:{ span=3 cap=964 }, 4:{ span=4 cap=925 }, 5:{ span=5 cap=964 }, 6:{ span=6 cap=967 }, 7:{ span=7 cap=967 } [ 2.158357] CPU1 attaching sched-domain(s): [ 2.158964] domain-0: span=0-7 level=MC [...]
Without this the NUMA domains are built correctly:
Without which? My patch, Ionela's patch, or both?
[ 2.008885] CPU0 attaching sched-domain(s): [ 2.009764] domain-0: span=0-1 level=MC [ 2.012654] groups: 0:{ span=0 cap=962 }, 1:{ span=1 cap=925 } [ 2.016532] domain-1: span=0-3 level=NUMA [ 2.017444] groups: 0:{ span=0-1 cap=1887 }, 2:{ span=2-3 cap=1871 } [ 2.019354] domain-2: span=0-5 level=NUMA
I'm not following this topology - what in the description above should result in a domain with span=0-5?
[ 2.019983] groups: 0:{ span=0-3 cap=3758 }, 4:{ span=4-5 cap=1935 } [ 2.021527] domain-3: span=0-7 level=NUMA [ 2.022516] groups: 0:{ span=0-5 mask=0-1 cap=5693 }, 6:{ span=4-7 mask=6-7 cap=3978 } [...]
Hope to see your comments since I have no Ampere machine and I don't know how to emulate its topology on qemu.
[1] bfcc4397435d ("arch_topology: Limit span of cpu_clustergroup_mask()")
Thanks, Yicong
Thanks,