WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Calculating real cpu usage of Xen domains correctly! (P

Subject: Re: [Xen-devel] Calculating real cpu usage of Xen domains correctly! (PATCH)
From: Rob Gardner <rob.gardner@xxxxxx>
Date: Sun, 27 Feb 2005 23:20:21 -0700
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxxx>
Delivery-date: Mon, 28 Feb 2005 06:22:54 +0000
Envelope-to: xen+James.Bulpin@xxxxxxxxxxxx
In-reply-to: <A95E2296287EAD4EB592B5DEEFCE0E9D1E32B8@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
References: <A95E2296287EAD4EB592B5DEEFCE0E9D1E32B8@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
User-agent: Mozilla Thunderbird 1.0 (Windows/20041206)
Ian Pratt wrote:
OK, here is a patch which provides fine grained cpu utilization reporting. Some notes:


I really can't see the point of this patch -- it isn't necessary to log
every scheduling operation to record CPU usage for a domain over
multiple time scales.

Yes, obviously you are correct. I am sorry for not explaining this patch better. Let me start from the beginning. We developed this code to collect various kinds of data. One of the things it does is measure cpu usage. However, that is not all it does, since as you rightly say, such complicated code is not necessary to to just measure cpu usage. When several people started talking about measuring cpu usage, I just volunteered this code to solve the problem. So I do not propose this code solely to measure cpu usage.

For instance, one thing the code can do is to measure how much time elapses while a domain is runnable, versus how much cpu time it actually receives. This metric might be one simple way of expressing 'quality of service.' In order to do this, some scheduler activity needs to be monitored. Hence the more heavy handed approach. We have other ideas in mind that require very fine grained measurements, some have been implemented, some not. I hope to share some of the other metrics soon.

Additionally, this is somewhat experimental code in that it was written this way in order to facilitate future measurements that we may not have considered yet. Can we let some people try it out and see if it provides this framework?

Thanks,
Rob


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel

<Prev in Thread] Current Thread [Next in Thread>