Support emulated NUMA for BCM2711 and BCM2712 #6273
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This PR also allows numa to be configured system wide (without directly using numactl) and enabled it by default through bootargs. @pelwell I'm sure the bootargs change is better in a lower level file. |
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It isn't possible to put some command line settings in a common file and add to/modify it elsewhere, but if there are some devices that share a common command line then we can put it in a common file and override it in its entirety where necessary. As it happens, of the BCM2711 devices, only CM4S has a different command line, and BCM2712 devices share the same one. Is this something you are thinking to enable by default on BCM2711 and BCM2712? |
Yes - enabled by default on BCM2711 and BCM2712 (ideally on all distributions) is the goal. |
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Bumped with a minor DT refactor. |
Add some common code for splitting the memory into N emulated NUMA memory nodes. Individual architecture can then enable selecting this option and use the existing numa=fake=<N> kernel argument to enable it. Memory is always split into equally sized chunks. Signed-off-by: Maíra Canal <mcanal@igalia.com> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com> Co-developed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: “Rafael J. Wysocki" <rafael@kernel.org>
Allow selecting NUMA emulation on arm64. Signed-off-by: Maíra Canal <mcanal@igalia.com> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: “Rafael J. Wysocki" <rafael@kernel.org>
Add numa_policy kernel argument to allow overriding the kernel's default NUMA policy at boot time. Syntax identical to what tmpfs accepts as it's mpol argument is accepted. Some examples: numa_policy=interleave numa_policy=interleave=skip-interleave numa_policy=bind:0-3,5,7,9-15 numa_policy=bind=static:1-2 Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
system_heap.max_order=<uint> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Most 2711 devices and all 2712 device share common bootargs (command lines). Make the common values shared defaults, overriding them were necessary. Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
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From: Tvrtko Ursulin tvrtko.ursulin@igalia.com
This series adds a very simple NUMA emulation implementation and enables
selecting it on arm64 platforms.
Obvious question is why? Short answer - it can bring a significant performance
uplift on Raspberry Pi 5.
Longer answer is that splitting the physical RAM into chunks, and utilising an
allocation policy such as interleaving, can enable the BCM2712 memory controller
to better utilise parallelism in physical memory chip organisation.
In more concrete numbers, testing with Geekbench 6 shows that splitting into four
emulated NUMA nodes can uplift the single core score of the benchmark by around
6%, and the multi-core by around 18%.
Code is quite simple and new functionality can be enabled using the new
NUMA_EMULATION Kconfig option and then at runtime using the existing (shared
with other platforms) numa=fake= kernel boot argument.