[Qemu-discuss] Specify number of cores for the guest

[Mahmood Naderan]

Hi,
I use the following command. Although I have specified 5 cores, in the windows guest, I see only one core in the task manager.
May I know what is wrong?
qemu-system-x86_64 -smp 5 -m 4096 -cpu Opteron_G5 -hda qemu-vm/win7_64.img -boot c  -usbdevice tablet -enable-kvm -device e1000,netdev=host_files -netdev user,net=10.0.2.0/24,id=host_files,restrict=off,smb=/export/home/theuser,smbserver=10.0.2.4


Regards,
Mahmood

[Lukas Straub]

Hello Mahmood,
That's because Qemu by default presents each CPU with it's own Socket
and Non-Server Windows (because of Licensing Reasons) supports only one
Socket. You should set it like: -smp cpus=1,cores=5
See https://qemu.weilnetz.de/doc/qemu-doc.html#index-_002dsmp

Regards,
Lukas Straub

On Sun, 2 Dec 2018 18:38:04 +0000 (UTC)

Post by Mahmood Naderan
Hi,
I use the following command. Although I have specified 5 cores, in
the windows guest, I see only one core in the task manager. May I
know what is wrong? qemu-system-x86_64 -smp 5 -m 4096 -cpu Opteron_G5
-hda qemu-vm/win7_64.img -boot c  -usbdevice tablet -enable-kvm
-device e1000,netdev=host_files -netdev
user,net=10.0.2.0/24,id=host_files,restrict=off,smb=/export/home/theuser,smbserver=10.0.2.4
Regards,
Mahmood

[Mahmood Naderan]

Post by Lukas Straub
That's because Qemu by default presents each CPU with it's own Socket
and Non-Server Windows (because of Licensing Reasons) supports only one
Socket. You should set it like: -smp cpus=1,cores=5
See https://qemu.weilnetz.de/doc/qemu-doc.html#index-_002dsmp

Even with "-smp cpus=1,cores=8" I get this error

cpu topology: sockets (1) * cores (8) * threads (1) > maxcpus (1)


Odd... Isn't it?

Regards,
Mahmood