Bug 42760 - Raise number of supported CPUs
Summary: Raise number of supported CPUs
Status: CLOSED FIXED
Alias: None
Product: Sisyphus
Classification: Development
Component: qemu (show other bugs)
Version: unstable
Hardware: x86 Linux
: P5 normal
Assignee: Alexey Shabalin
QA Contact: qa-sisyphus
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-05-13 22:58 MSK by Vitaly Chikunov
Modified: 2024-07-24 11:46 MSK (History)
4 users (show)

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Description Vitaly Chikunov 2022-05-13 22:58:22 MSK 
+ qemu-system-x86_64 -smp cores=1111 ...
qemu-system-x86_64: Invalid SMP CPUs 1111. The max CPUs supported by machine 'pc-i440fx-6.2' is 255

+ qemu-system-x86_64 -M q35 -smp cores=1111 ...
qemu-system-x86_64: Invalid SMP CPUs 1111. The max CPUs supported by machine 'pc-q35-6.2' is 288
Comment 1 Vitaly Chikunov 2022-05-13 23:07:06 MSK 
Возможно, больше 1024 поднимать не имеет смысла так как, на x86-64 есть ещё не изменяемый лимит

  #define KVM_MAX_VCPUS 1024
Comment 2 Vitaly Chikunov 2022-05-13 23:21:01 MSK 
https://access.redhat.com/articles/rhel-kvm-limits
Intel 64 and AMD64: Red Hat Enterprise Linux 8 Server with KVM
Maximum number of virtual CPUs in virtualized guest 384

https://access.redhat.com/articles/906543
Virtual Machine Maximums:
710 for RHV 4.4 (710 for Q35 machines, 240 for PC machines)

Host Maximums:
Logical CPU cores or threads: 768
Comment 3 Alexey Shabalin 2024-07-20 17:10:26 MSK 
$qemu-system-x86_64 --version
QEMU emulator version 8.2.4 (qemu-8.2.4-alt1)

$qemu-system-x86_64 -M q35 -smp cores=1111
qemu-system-x86_64: Invalid SMP CPUs 1111. The max CPUs supported by machine 'pc-q35-8.2' is 1024

Оставляем как есть? ничего не делаем?
Comment 4 Alexey Shabalin 2024-07-20 17:24:38 MSK 
$qemu-system-x86_64 --version
QEMU emulator version 9.0.2 (qemu-9.0.2-alt1)

$qemu-system-x86_64 -M q35 -smp cores=5555
qemu-system-x86_64: Invalid SMP CPUs 5555. The max CPUs supported by machine 'pc-q35-9.0' is 4096
Comment 5 Vitaly Chikunov 2024-07-20 17:45:38 MSK 
Думаю достаточно, даже слишком много. 255 было меньше чем на реальных машинах с 256 cores.