search for: autonuma

Regarding the presentation I gave at the kvm forum on pagefaults. Two points: 1. pagefaults are important not just for migration. They are important for performance features such as autonuma and huge pages, since this relies on moving pages around. Migration can maybe be solved by switch to software but this is not a good solution for numa and thp since at a given time some page is likely being moved. 2. For devices such as networking RX order in which buffers are used *does not...

Hi For a school project I am researching performance issues when using libvirt to run very large numbers of virtual machines. My experiments indicate that having more CPU cores negatively impacts the performance. A simple desktop with an Intel Core 2 Duo E6550 performs better than a server with a 48 core AMD CPU. Limiting the cores used through 'cputune' improves performance on the

...data pages (belongs to co-operate processes) itself is > still questionable I am not sure why. It should be easy enough to force the VCPU and vhost to move (e.g. start them pinned to 1 cpu, then pin them to another one). Clearly sometimes this would be necessary for load balancing reasons. With autonuma after a while (could take seconds but it will happen) the memory will migrate. > > > > > > > > > > > > > > This is the price of all GUP users not only vhost itself. > > > > Yes. GUP is just not a great interface for vhost to use. > &...

...data pages (belongs to co-operate processes) itself is > still questionable I am not sure why. It should be easy enough to force the VCPU and vhost to move (e.g. start them pinned to 1 cpu, then pin them to another one). Clearly sometimes this would be necessary for load balancing reasons. With autonuma after a while (could take seconds but it will happen) the memory will migrate. > > > > > > > > > > > > > > This is the price of all GUP users not only vhost itself. > > > > Yes. GUP is just not a great interface for vhost to use. > &...

...(e.g. start them pinned to 1 cpu, then pin them to another one). > > Clearly sometimes this would be necessary for load balancing reasons. > > > Yes, but it looks to me the part of motivation of auto NUMA is to avoid > manual pinning. ... of memory. Yes. > > > With autonuma after a while (could take seconds but it will happen) the > > memory will migrate. > > > > Yes. As you mentioned during the discuss, I wonder we could do it similarly > through mmu notifier like APIC access page in commit c24ae0dcd3e ("kvm: x86: > Unpin and remove kvm...

...(e.g. start them pinned to 1 cpu, then pin them to another one). > > Clearly sometimes this would be necessary for load balancing reasons. > > > Yes, but it looks to me the part of motivation of auto NUMA is to avoid > manual pinning. ... of memory. Yes. > > > With autonuma after a while (could take seconds but it will happen) the > > memory will migrate. > > > > Yes. As you mentioned during the discuss, I wonder we could do it similarly > through mmu notifier like APIC access page in commit c24ae0dcd3e ("kvm: x86: > Unpin and remove kvm...

...gt; > > > Clearly sometimes this would be necessary for load balancing reasons. > > > > > > Yes, but it looks to me the part of motivation of auto NUMA is to avoid > > > manual pinning. > > ... of memory. Yes. > > > > > > > > With autonuma after a while (could take seconds but it will happen) the > > > > memory will migrate. > > > > > > > Yes. As you mentioned during the discuss, I wonder we could do it similarly > > > through mmu notifier like APIC access page in commit c24ae0dcd3e ("k...

...pinned to 1 cpu, then pin them to another one). >>> Clearly sometimes this would be necessary for load balancing reasons. >> >> Yes, but it looks to me the part of motivation of auto NUMA is to avoid >> manual pinning. > ... of memory. Yes. > > >>> With autonuma after a while (could take seconds but it will happen) the >>> memory will migrate. >>> >> Yes. As you mentioned during the discuss, I wonder we could do it similarly >> through mmu notifier like APIC access page in commit c24ae0dcd3e ("kvm: x86: >> Unpin and...

...be easy enough to force the VCPU and vhost > to move (e.g. start them pinned to 1 cpu, then pin them to another one). > Clearly sometimes this would be necessary for load balancing reasons. Yes, but it looks to me the part of motivation of auto NUMA is to avoid manual pinning. > With autonuma after a while (could take seconds but it will happen) the > memory will migrate. > Yes. As you mentioned during the discuss, I wonder we could do it similarly through mmu notifier like APIC access page in commit c24ae0dcd3e ("kvm: x86: Unpin and remove kvm_arch->apic_access_page&qu...

On Mon, Dec 24, 2018 at 03:53:16PM +0800, Jason Wang wrote: > > On 2018/12/14 ??8:36, Michael S. Tsirkin wrote: > > On Fri, Dec 14, 2018 at 11:57:35AM +0800, Jason Wang wrote: > > > On 2018/12/13 ??11:44, Michael S. Tsirkin wrote: > > > > On Thu, Dec 13, 2018 at 06:10:22PM +0800, Jason Wang wrote: > > > > > It was noticed that the copy_user()

On Mon, Dec 24, 2018 at 03:53:16PM +0800, Jason Wang wrote: > > On 2018/12/14 ??8:36, Michael S. Tsirkin wrote: > > On Fri, Dec 14, 2018 at 11:57:35AM +0800, Jason Wang wrote: > > > On 2018/12/13 ??11:44, Michael S. Tsirkin wrote: > > > > On Thu, Dec 13, 2018 at 06:10:22PM +0800, Jason Wang wrote: > > > > > It was noticed that the copy_user()