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| author | Srikar Dronamraju <srikar@linux.vnet.ibm.com> | 2020-09-21 15:26:44 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-10-06 23:22:26 +1100 |
| commit | 4ca234a9cbd7c3a656b34dd98c8b156f70ed7849 (patch) | |
| tree | 84674ae66b7c470490aac8012a8b098f95b2db95 /arch/powerpc/boot/stdlib.h | |
| parent | 4bce545903fa0290e011cf118997717f0c4f4d20 (diff) | |
powerpc/smp: Stop updating cpu_core_mask
Anton Blanchard reported that his 4096 vcpu KVM guest took around 30
minutes to boot. He also analyzed it to the time taken to iterate while
setting the cpu_core_mask.
Further analysis shows that cpu_core_mask and cpu_cpu_mask for any CPU
would be equal on Power. However updating cpu_core_mask took forever to
update as its a per cpu cpumask variable. Instead cpu_cpu_mask was a per
NODE /per DIE cpumask that was shared by all the respective CPUs.
Also cpu_cpu_mask is needed from a scheduler perspective. However
cpu_core_map is an exported symbol. Hence stop updating cpu_core_map
and make it point to cpu_cpu_mask.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200921095653.9701-3-srikar@linux.vnet.ibm.com
Diffstat (limited to 'arch/powerpc/boot/stdlib.h')
0 files changed, 0 insertions, 0 deletions