From mboxrd@z Thu Jan  1 00:00:00 1970
From: John Byrne <john.l.byrne@hp.com>
Subject: Live migration: "netbuf race" messages can cause
 significant perfomance impact
Date: Wed, 20 Dec 2006 19:00:16 -0800
Message-ID: <4589F8C0.30809@hp.com>
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Hi,

Someone found that doing a live migration of a domain that had ballooned 
down took far longer to migrate. (Ballooned down from 3000M to 1000M, 31 
seconds vs 89 seconds, real time) I came up with a complex theory and 
asked him to look in the xend.log to confirm it. He didn't, but he 
mentioned there was a lot of "netbuf race" messages in the log. In this 
particular case, live migration generated approximately 512000 "netbuf 
race" messages. Deleting the DPRINTF reduced the migration time to 11 
seconds.

While it is simple enough to submit a patch to delete this DPRINTF, 
perhaps something more subtle is called for such as modifying the 
migrate/save command paths to accept a debug argument and passing to 
xc_save?

Thanks,

John Byrne