Re: [hwloc-users] Support for Intel's hybrid architecture - can I restrict hwloc-distrib to P cores only?
Thank you, Brice! I'm testing it on a Lenovo P1 laptop with an i7-12800H CPU with 6P + 8E. --cpukinds option solves the problem for me:-) hwloc-calc --cpukind 1 all BTW, Intel's patches to improve Linux scheduling on hybrid architectures were significantly improved this year and released recently in kernel version 6.6. https://www.phoronix.com/news/Intel-Hybrid-Cluster-Sched-v3 Jirka On Fri, Nov 24, 2023 at 9:19 AM Brice Goglin wrote: > > Le 24/11/2023 à 08:51, John Hearns a écrit : > > Good question. Maybe not an answer referring to hwloc. > > When managing a large NUMA machine, SGI UV, I ran the OS processes in > > a boot cpuset which was restricted to (AFAIR) the first 8 Cpus. > > On Intel architecures with E and P cores could we think of running OS > > on E cores only and having the batch system schedule compute tasks on > > P cores? > > > > That's certainly possible. Linux has things like isolcpus to force > isolate some cores away from the OS tasks, should work for these > platforms too (by the way, it's also for ARM big.LITTLE platforms > running Linux, including Apple M1, etc). > > However, keep in mind that splitting P+E CPUs is not like splitting NUMA > platforms: isolating NUMA node #0 on SGI left tons of cores available > for HPC tasks on NUMA nodes. Current P+E from Intel usually have more E > than P, and several models are even 2P+8E, that would be a lot of > E-cores for the OS and very few P-cores for real apps. Your idea would > apply better if we rather had 2E+8P but that's not the trend. > > Things might be more interesting with MeteorLake which (according to > > https://www.hardwaretimes.com/intel-14th-gen-meteor-lake-cpu-cores-almost-identical-to-13th-gen-its-a-tic/) > > has P+E as usual but also 2 "low-power E" on the side. There, you could > put the OS on those 2 Low-Power E. > > By the way, the Linux scheduler is supposed to get enhanced to > automatically find out which tasks to put on P and E core but they've > been discussing things for a long time and it's hard to know what's > actually working well already. > > Brice > > > ___ > hwloc-users mailing list > hwloc-users@lists.open-mpi.org > https://lists.open-mpi.org/mailman/listinfo/hwloc-users -- -Jirka ___ hwloc-users mailing list hwloc-users@lists.open-mpi.org https://lists.open-mpi.org/mailman/listinfo/hwloc-users
Re: [hwloc-users] Support for Intel's hybrid architecture - can I restrict hwloc-distrib to P cores only?
Le 24/11/2023 à 08:51, John Hearns a écrit : Good question. Maybe not an answer referring to hwloc. When managing a large NUMA machine, SGI UV, I ran the OS processes in a boot cpuset which was restricted to (AFAIR) the first 8 Cpus. On Intel architecures with E and P cores could we think of running OS on E cores only and having the batch system schedule compute tasks on P cores? That's certainly possible. Linux has things like isolcpus to force isolate some cores away from the OS tasks, should work for these platforms too (by the way, it's also for ARM big.LITTLE platforms running Linux, including Apple M1, etc). However, keep in mind that splitting P+E CPUs is not like splitting NUMA platforms: isolating NUMA node #0 on SGI left tons of cores available for HPC tasks on NUMA nodes. Current P+E from Intel usually have more E than P, and several models are even 2P+8E, that would be a lot of E-cores for the OS and very few P-cores for real apps. Your idea would apply better if we rather had 2E+8P but that's not the trend. Things might be more interesting with MeteorLake which (according to https://www.hardwaretimes.com/intel-14th-gen-meteor-lake-cpu-cores-almost-identical-to-13th-gen-its-a-tic/) has P+E as usual but also 2 "low-power E" on the side. There, you could put the OS on those 2 Low-Power E. By the way, the Linux scheduler is supposed to get enhanced to automatically find out which tasks to put on P and E core but they've been discussing things for a long time and it's hard to know what's actually working well already. Brice OpenPGP_signature Description: OpenPGP digital signature ___ hwloc-users mailing list hwloc-users@lists.open-mpi.org https://lists.open-mpi.org/mailman/listinfo/hwloc-users
Re: [hwloc-users] Support for Intel's hybrid architecture - can I restrict hwloc-distrib to P cores only?
Le 23/11/2023 à 19:29, Jirka Hladky a écrit : Hi Brice, I have a question about the hwloc's support for Intel's hybrid architectures, like in Alder Lake CPUs: https://en.wikipedia.org/wiki/Alder_Lake There are P (performance) and E (efficiency) cores. Is hwloc able to detect which core is which? Can I, for example, restrict hwloc-distrib to P cores only? Pseudocode: hwloc-distrib --single --restrict <> <> Hello On machines with 2 kinds of cores (P and E), P are the second cpukinds in hwloc (cpukinds are ordered by energy-efficiency first): $ lstopo --cpukinds CPU kind #0 efficiency 0 cpuset 0x000ff000 CoreType = IntelAtom CPU kind #1 efficiency 1 cpuset 0x0fff CoreType = IntelCore These cpusets may be returned by hwloc-calc either by index or by info attribute: $ hwloc-calc --cpukind 1 all 0x0fff $ hwloc-calc --cpukind CoreType=IntelCore all 0x0fff So just pass --restrict $(hwloc-calc --cpukind 1 all) to hwloc-distrib and you should be good. Brice OpenPGP_signature Description: OpenPGP digital signature ___ hwloc-users mailing list hwloc-users@lists.open-mpi.org https://lists.open-mpi.org/mailman/listinfo/hwloc-users
Re: [hwloc-users] Support for Intel's hybrid architecture - can I restrict hwloc-distrib to P cores only?
Good question. Maybe not an answer referring to hwloc. When managing a large NUMA machine, SGI UV, I ran the OS processes in a boot cpuset which was restricted to (AFAIR) the first 8 Cpus. On Intel architecures with E and P cores could we think of running OS on E cores only and having the batch system schedule compute tasks on P cores? On Thu, 23 Nov 2023 at 18:31, Jirka Hladky wrote: > Hi Brice, > > I have a question about the hwloc's support for Intel's hybrid > architectures, like in Alder Lake CPUs: > https://en.wikipedia.org/wiki/Alder_Lake > > There are P (performance) and E (efficiency) cores. Is hwloc able to > detect which core is which? Can I, for example, restrict hwloc-distrib to P > cores only? > > Pseudocode: > hwloc-distrib --single --restrict <> <> > > Merci beaucoup! > Jirka > > > > ___ > hwloc-users mailing list > hwloc-users@lists.open-mpi.org > https://lists.open-mpi.org/mailman/listinfo/hwloc-users ___ hwloc-users mailing list hwloc-users@lists.open-mpi.org https://lists.open-mpi.org/mailman/listinfo/hwloc-users
