The plugin, when set to poll for changes (i.e. non-zero value of Multi-site poll buffer), will check for any changes on the branch or stream in question since the previous build started. When one or more of the branches/streams being polled against are mastered at another site and are synced to the site Jenkins is polling at via MultiSite, this may result in problems polling against changes made to remote branches/streams before the previous build started, but which weren't synced to the local site until after the previous build started.

To compensate for this, you may specify a buffer, in minutes, to subtract from the previous build time to generate the time to poll against. While this is not optimal (if a change occured on a local branch/stream being polled against during the MultiSite poll buffer before the previous build, the next poll will detect that change and kick off a new build, etc), it should allow for guaranteeing that changes from remote sites aren't missed.

If this value is set to 0 (the default), no buffer is used. Also, instead of checking for changes since last build, only changes since last poll will be detected.