search for: undersubscribed

In the real world (or at least in my world) we use undersubscribed internet connections that come with a service level agreement (SLA) that guarantees that the jitter, delay, and packet loss with be within defined parameters in the service agreement. With most DSL and Cable you will not get a SLA, with the cheapest T1s you might get one, but the only penalty to t...

...es packet buffers). There are only two ways to get acceptable performance; 1. use a private or managed link between your VoIP endpoints and prioritize the RTP streams between the endpoints, leaving the jitter, delay, and packet loss for the data apps. Or 2. use public unmanaged links that are way undersubscribed so there is never any contention for bandwidth, because contention for bandwidth is he number one cause of jitter, delay, and packet loss. Most consumer broadband systems do not fall into the undersubscribed category whereas most T1 and above commercial services are much closer to undersubscribed....

Ankur Arora <ankur.a.arora at oracle.com> writes: > A KVM host (or another hypervisor) might advertise paravirtualized > features and optimization hints (ex KVM_HINTS_REALTIME) which might > become stale over the lifetime of the guest. For instance, the > host might go from being undersubscribed to being oversubscribed > (or the other way round) and it would make sense for the guest > switch pv-ops based on that. If your host changes his advertised behaviour then you want to fix the host setup or find a competent admin. > This lockorture splat that I saw on the guest while testi...

...ue, Apr 07, 2020 at 10:02:57PM -0700, Ankur Arora wrote: > A KVM host (or another hypervisor) might advertise paravirtualized > features and optimization hints (ex KVM_HINTS_REALTIME) which might > become stale over the lifetime of the guest. For instance, the > host might go from being undersubscribed to being oversubscribed > (or the other way round) and it would make sense for the guest > switch pv-ops based on that. So what, the paravirt spinlock stuff works just fine when you're not oversubscribed. > We keep an interesting subset of pv-ops (pv_lock_ops only for now, > but P...

...ue, Apr 07, 2020 at 10:02:57PM -0700, Ankur Arora wrote: > A KVM host (or another hypervisor) might advertise paravirtualized > features and optimization hints (ex KVM_HINTS_REALTIME) which might > become stale over the lifetime of the guest. For instance, the > host might go from being undersubscribed to being oversubscribed > (or the other way round) and it would make sense for the guest > switch pv-ops based on that. So what, the paravirt spinlock stuff works just fine when you're not oversubscribed. > We keep an interesting subset of pv-ops (pv_lock_ops only for now, > but P...

...> A KVM host (or another hypervisor) might advertise paravirtualized > features and optimization hints (ex KVM_HINTS_REALTIME) which might > become stale over the lifetime of the guest. For instance, the Then this hint is wrong if it can't be guaranteed. > host might go from being undersubscribed to being oversubscribed > (or the other way round) and it would make sense for the guest > switch pv-ops based on that. I think using pvops for such a feature change is just wrong. What comes next? Using pvops for being able to migrate a guest from an Intel to an AMD machine? ... > The...

Hi all, this series adds multiqueue support to the virtio-scsi driver, based on Jason Wang's work on virtio-net. It uses a simple queue steering algorithm that expects one queue per CPU. LUNs in the same target always use the same queue (so that commands are not reordered); queue switching occurs when the request being queued is the only one for the target. Also based on Jason's

Hi all, this series adds multiqueue support to the virtio-scsi driver, based on Jason Wang's work on virtio-net. It uses a simple queue steering algorithm that expects one queue per CPU. LUNs in the same target always use the same queue (so that commands are not reordered); queue switching occurs when the request being queued is the only one for the target. Also based on Jason's