Xen 4.2 will contain two new scheduling parameters for the credit1 scheduler which significantly increase its confurability and performance for cloud-based workloads: timeslice_ms and ratelimit_us. This blog post describes what they do, and how to configure them for best performance.
Timeslice
The timeslice for the credit1 has historically been fixed at 30ms. This is actually a fairly long time — it’s great for computationally-intensive workloads, but not so good for latency-sensitive workloads, particularly ones involving network traffic or audio.
Xen 4.2 introduces the tslice_ms parameter, which sets the timeslice of the scheduler in milliseconds. This can be set either using the Xen command-line option, sched_credit_tslice_ms, or by using the new scheduling parameter interface to xl sched-credit:
# xl sched-credit -t [n]
Continued…
Posted in Xen Hypervisor.
Tagged with credit1, scheduler, Xen 4.2, Xen Hypervisor.
By dunlapg
– April 10, 2012
Today, Citrix and the Apache Software Foundation (ASF) announced that it will relicense the CloudStack open source project under the Apache License and contribute the CloudStack code to the ASF. Before I explain why this is good for the Xen community and the Open Cloud, I wanted to congratulate CloudStack to become the first cloud platform in the industry to join the ASF.
CloudStack has always been open source, with Citrix as the vendor behind the project. Moving from a privately operated open source community to the ASF has a number of implications: Citrix is giving up control over the project and it is moving to a collaborative and meritocratic development process, which values community, diversity and openness. For a community guy like me this is really exciting!
So why is this good news for Xen? In fact, the internal discussions preceding this decision already made a big impact: more staff within Citrix are engaged with open source and are actively supporting and understanding projects such as Xen, Linux and of course CloudStack. My experience as open source guy in various organisations is that open source and community can be easily made the responsibility of a few people and then be forgotten about. However, to be truly successful in the long haul, knowledge and support for open source in an organization needs to be broad. In the last few months the level of understanding and support for Xen across Citrix has increased hugely. You may not yet see the impact of all this: good initiatives and change need planning and take time. Don’t get me wrong: on many counts Xen is a very successful project. We have an active developer community, we have a huge user base, many successful products and businesses were built on Xen, etc. But the project could have done and can do better!
When I was at Scale 10x earlier this year, Greg DeKoenigsberg from Eucalyptus said in his keynote that most cloud projects are open source today, well sort of! To me that said it all: the more cloud related projects move from single vendor driven projects to independent and community driven projects, the better for the user and the “Open Cloud”. Why? Simple: independent projects increase the user’s ability to be in control of their infrastructure by influencing the projects they care about. Thus, CloudStack becoming an Apache project, is a major milestone for achieving a better and more open cloud. Of course, the same thinking lies behind the creation of the OpenStack Foundation, which we will hopefully see later this year.
Posted in Partner Announcements.
Tagged with Apache, Cloudstack, Open Source.
By Lars
– April 3, 2012
We have hit the next milestone in the release plan for Xen 4.2:
19 March — TODO list locked down- 2 April — Feature Freeze WE ARE HERE
- Mid/Late April — First release candidate
- Weekly — RCN+1 until it is ready
We are therefore now in Feature Freeze for Xen 4.3! Patches which have been posted before or which address something on the TODO list are still acceptable (for now, we will gradually be getting stricter about this), everything else will be deferred until 4.3 by default.
Posted in Xen Development, Xen Hypervisor.
Tagged with Release Planning, Xen 4.2.
By ijc
– April 2, 2012
Since early January I have been tracking the status of work left to do before 4.2 by posting a weekly roundup of the remaining blockers and “nice to haves”. You can find these in the xen devel list archives, posted most Monday mornings.
Last week I decided that the TODO list had reached the point where it was time to start thinking about a release. I made a proposal for a release timeline which was generally agreed to be a reasonable plan.
In summary the plan is as follows (see the list posting for more details):
- 19 March — TODO list locked down WE ARE HERE
- 2 April — Feature Freeze
- Mid/Late April — First release candidate
- Weekly — RCN+1 until it is ready
The aim is to have a release around June time although as always this will be subject to the usual “when it is ready” test.
The TODO list was reposted this morning and contains the latest blockers and nice to haves.
Posted in Xen Development, Xen Hypervisor.
Tagged with Release Planning, Xen 4.2.
By ijc
– March 19, 2012
Virtual Build a Cloud Day will be dedicated to teaching users how to build and manage a cloud computing environment using free and open source software. The program is designed to expose attendees to the concepts and best practices around deploying cloud computing infrastructure.
I’ll be presenting the XCP talk tomorrow:
http://cloudstack.org/about-cloudstack/cloudstack-events/viewevent/52-virtual-build-a-cloud-day-session-1.html#Deshane
For more details of the event see:
http://cloudstack.org/about-cloudstack/cloudstack-events.html?categoryid=6
Even if you can’t attend all the sessions feel free to sign-up and we’ll make our best effort to get you links to recordings and slide decks after the event.
Posted in Uncategorized.
By deshantm
– February 27, 2012
