[Qemu-devel] cgroup blkio weight has no effect on qemu

[陈博]

Hi folks,


Could you enlighten me how to achieve proportional IO sharing by using cgroup, 
instead of qemu's io-throttling?

My qemu config is like: -drive 
file=$DISKFILe,if=none,format=qcow2,cache=none,aio=native -device 
virtio-blk-pci...

Test command inside vm is like: dd if=/dev/vdc of=/dev/null iflag=direct

Cgroup blkio weight of the qemu process is properly configured as well.

But no matter how change the proportion, such as vm1=400 and vm2=100, I can 
only get the equal IO speed.

Wondering cgroup blkio.weight or blkio.weight_device has no effect on qemu?


PS. cache=writethrough aio=threads is also tested, the same results. 


- Bob

Re: [Qemu-devel] [PATCH v4 0/3] add avx2 instruction optimization

[陈博]

Sorry for disturbing by reply, don't know why I'm not able to send a new mail.


Hi folks,

Could you enlighten me how to achieve proportional IO sharing by using cgroup, 
instead of qemu's io-throttling?

My qemu config is like: -drive 
file=$DISKFILe,if=none,format=qcow2,cache=none,aio=native -device 
virtio-blk-pci...

Test command inside vm is like: dd if=/dev/vdc of=/dev/null iflag=direct

Cgroup blkio weight of the qemu process is properly configured as well.

But no matter how change the proportion, such as vm1=400 and vm2=100, I can 
only get the equal IO speed.

Wondering cgroup blkio.weight or blkio.weight_device has no effect on qemu?


PS. cache=writethrough aio=threads is also tested, the same results. 


- Bob



在 2016年1月20日，下午5:05，Liang Li  写道：

> buffer_find_nonzero_offset() is a hot function during live migration.
> 

[Qemu-devel] cgroup blkio weight has no effect on qemu

[陈博]

Hi,


Could you enlighten me how to achieve proportional IO sharing by using cgroup, 
instead of qemu's own io-throttling?

My qemu config is like: -drive 
file=$DISKFILe,if=none,format=qcow2,cache=none,aio=native -device 
virtio-blk-pci...

Test command inside vm is like: dd if=/dev/vdc of=/dev/null iflag=direct

Cgroup blkio weight of the qemu process is properly configured as well.

But no matter how change the proportion, such as vm1=400 and vm2=100, I can 
only get the equal IO speed.

Wondering cgroup blkio.weight or blkio.weight_device has no effect on qemu?


PS. cache=writethrough aio=threads is also tested, the same results. 


- Bob

[Qemu-devel] cgroup blkio weight has no effect for qemu

[陈博]

Hi folks,


Could you please enlighten me about how to achieve proportional IO sharing by 
using cgroup, instead of qemu?

My qemu config is like: -drive 
file=$DISKFILe,if=none,format=qcow2,cache=none,aio=native

Test command inside vm is like: dd if=/dev/vdc of=/dev/null iflag=direct

Cgroup blkio weight of the qemu process is properly configured as well.

But no matter how change the proportion, such as vm1=400 and vm2=100, I can 
only get the equal IO speed.

Wondering cgroup blkio.weight or blkio.weight_device has no effect for qemu???


PS. cache=writethrough aio=threads is also tested, the same results. 



- Bob

[Qemu-devel] cgroup blkio weight has no effect on qemu

[陈博]

Hi folks,


Could you enlighten me about how to achieve proportional IO sharing by using 
cgroup, instead of qemu?

My qemu config is like: -drive 
file=$DISKFILe,if=none,format=qcow2,cache=none,aio=native

Test command inside vm is like: dd if=/dev/vdc of=/dev/null iflag=direct

Cgroup blkio weight of the qemu process is properly configured as well.

But no matter how change the proportion, such as vm1=400 and vm2=100, I can 
only get the equal IO speed.

Wondering cgroup blkio.weight or blkio.weight_device has no effect on qemu???


PS. cache=writethrough aio=threads is also tested, the same results. 



- Bob

[Qemu-devel] QEMU using hugepage

[陈博]

Hi,

My host os is CentOS6, to avoid being affected by the unstable Transparent 
Hugepage feature, I started to pre-allocate memory for qemu by using the kernel 
native hugepage.

What I’m asking here is, if the guest set huge page inside itself as well (very 
large guest, 32 core 128G for instance), what would happen?

Will the performance keeps on rising a little bit?

Is it really necessary to set hugepage for qemu anyway?


Regards, 
Bob