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[Xen-devel] Re: VM disk I/O limit patch

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] Re: VM disk I/O limit patch
From: Shaun Reitan <mailinglists@xxxxxxxxxxxxxxxx>
Date: Thu, 23 Jun 2011 13:45:36 -0700
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Does this match only limit throughput or can it also limit the guest by disk IOPS? christopher aker had a patch way back for UML that did disk based qos. What i really liked about that patch was that it allowed for bursting by using a bucket. If i remember correctly you specified that a guest's bucket could hold say 4000 tokens, and the bucket would be filled with 10 tokens a second. Each IO took one token from the bucket. When the bucket was empty IO was paused and processed as the bucket was filled. This allowed a guest to burst for a short period of time until that bucket was empty and then it would slowely be filled back up.

Also what was nice is that the guest had a /proc/ entry that told the customer how many tokens they currently had in their bucket.

I would like to see somthing like this in Xen, I've even thought about posting to the devel forums seeing if somebody wanted to write one for $$$

~Shaun


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