Re: [libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2018-03-27 Thread Sergio Lopez
Hi, I'd like to resurrect this thread: https://www.redhat.com/archives/libvir-list/2017-February/msg01084.html Recent benchmarks have demonstrated that using large values for poll-max-ns significantly decreases the perceived latency in the Guest, at the expense of the iothread using more CPU:

Re: [libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2017-02-21 Thread Stefan Hajnoczi
On Tue, Feb 21, 2017 at 1:39 PM, Pavel Hrdina wrote: > On Tue, Feb 21, 2017 at 01:26:25PM +, Daniel P. Berrange wrote: >> On Tue, Feb 21, 2017 at 02:14:44PM +0100, Pavel Hrdina wrote: >> > On Tue, Feb 21, 2017 at 12:55:51PM +, Daniel P. Berrange wrote: >> > > On Tue, Feb 21, 2017 at 01:48:

Re: [libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2017-02-21 Thread Pavel Hrdina
On Tue, Feb 21, 2017 at 01:26:25PM +, Daniel P. Berrange wrote: > On Tue, Feb 21, 2017 at 02:14:44PM +0100, Pavel Hrdina wrote: > > On Tue, Feb 21, 2017 at 12:55:51PM +, Daniel P. Berrange wrote: > > > On Tue, Feb 21, 2017 at 01:48:15PM +0100, Pavel Hrdina wrote: > > > > On Tue, Feb 21, 201

Re: [libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2017-02-21 Thread Daniel P. Berrange
On Tue, Feb 21, 2017 at 02:14:44PM +0100, Pavel Hrdina wrote: > On Tue, Feb 21, 2017 at 12:55:51PM +, Daniel P. Berrange wrote: > > On Tue, Feb 21, 2017 at 01:48:15PM +0100, Pavel Hrdina wrote: > > > On Tue, Feb 21, 2017 at 12:26:02PM +, Daniel P. Berrange wrote: > > > > On Tue, Feb 21, 201

Re: [libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2017-02-21 Thread Pavel Hrdina
On Tue, Feb 21, 2017 at 12:55:51PM +, Daniel P. Berrange wrote: > On Tue, Feb 21, 2017 at 01:48:15PM +0100, Pavel Hrdina wrote: > > On Tue, Feb 21, 2017 at 12:26:02PM +, Daniel P. Berrange wrote: > > > On Tue, Feb 21, 2017 at 01:14:57PM +0100, Pavel Hrdina wrote: > > > > QEMU 2.9.0 will int

Re: [libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2017-02-21 Thread Daniel P. Berrange
On Tue, Feb 21, 2017 at 01:48:15PM +0100, Pavel Hrdina wrote: > On Tue, Feb 21, 2017 at 12:26:02PM +, Daniel P. Berrange wrote: > > On Tue, Feb 21, 2017 at 01:14:57PM +0100, Pavel Hrdina wrote: > > > QEMU 2.9.0 will introduce polling feature for AioContext that instead > > > of blocking syscall

Re: [libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2017-02-21 Thread Pavel Hrdina
On Tue, Feb 21, 2017 at 12:26:02PM +, Daniel P. Berrange wrote: > On Tue, Feb 21, 2017 at 01:14:57PM +0100, Pavel Hrdina wrote: > > QEMU 2.9.0 will introduce polling feature for AioContext that instead > > of blocking syscalls polls for events without blocking. This means > > that polling can

Re: [libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2017-02-21 Thread Daniel P. Berrange
On Tue, Feb 21, 2017 at 01:14:57PM +0100, Pavel Hrdina wrote: > QEMU 2.9.0 will introduce polling feature for AioContext that instead > of blocking syscalls polls for events without blocking. This means > that polling can be in most cases faster but it also increases CPU > utilization. > > To add

[libvirt] [PATCH 01/12] conf: introduce domain XML element for iothread

2017-02-21 Thread Pavel Hrdina
QEMU 2.9.0 will introduce polling feature for AioContext that instead of blocking syscalls polls for events without blocking. This means that polling can be in most cases faster but it also increases CPU utilization. To address this issue QEMU implements self-tuning algorithm that modifies the cu