KVM call agenda for 2013-04-09
Hi
Please send in any agenda topics you are interested in.
Later, Juan.
Quoted 1 line · Juan Quintela
Hi
Today there is a call, there was agenda but I didn't noticed that it was sent as private mail to me:
Quoted 1 line
From Abel Gordon:
I would like to present a technical report we just published that describes the design and evaluation of the work we did to improve virtual net/block I/O scalability and performance based on vhost and hosting multiple KVM guests.
We started some discussion in the qemu-mailing list about this work and dataplane:
http://lists.gnu.org/archive/html/qemu-devel/2013-02/msg02702.html
http://lists.gnu.org/archive/html/qemu-devel/2013-03/msg00028.html
The report can be downloaded from the following link: http://goo.gl/RKppy
(full link:
)
Meeting notes on Abel's presentation:
Aim: improve vhost scalability
Shared vhost thread
==============
Problem: Linux scheduler does not see state of virtqueues, cannot make good scheduling decisions
Solution: Shared thread serves multiple VMs and therefore influences "I/O scheduling" instead of kernel thread per vhost device
Exitless communication
=================
* Polling on host to notice guest vring updates without guest pio instruction
* Use CPU affinity to bind vcpus to separate cores and let polling
run on dedicated cores
* Existless Interrupt (ELI) or future hardware APIC virtualization
feature to inject virtual interrupts
without vmexit and EOI
See paper for performance results (impressive numbers):
http://domino.research.ibm.com/library/cyberdig.nsf/papers/479E3578ED05BFAC85257B4200427735/$File/h-0319.pdf
Abel will publish rebased code on GitHub but does not have time to upstream them.
The next step: QEMU/KVM community can digest the paper + patches and decide on ideas to upstream.