Daniel P. Berrangé <berra...@redhat.com> wrote: > The 'unsigned int interations' config for migration is somewhat > overkill. Most tests don't set it, and a value of '0' is treated > as equivalent to '1'. The only test that does set it, xbzrle, > used a value of '2'. > > This setting, however, only relates to the migration iterations > that take place prior to allowing convergence. IOW, on top of > this iteration count, there is always at least 1 further migration > iteration done to deal with pages that are dirtied during the > previous iteration(s). > > IOW, even with iterations==1, the xbzrle test will be running for > a minimum of 2 iterations. With this in mind we can simplify the > code and just get rid of the special case.
Perhaps the old code was already wrong, but we need at least three iterations for the xbzrle test: - 1st iteration: xbzrle is not used, nothing is on cache. - 2nd iteration: pages are put into cache, no xbzrle is used because there is no previous page. - 3rd iteration: We really use xbzrle now against the copy of the previous iterations. And yes, this should be commented somewhere. Later, Juan.
