On Fri, Dec 3, 2010 at 12:19 AM, Edward J. Yoon <[email protected]> wrote: > Oh, Is HAMA-331 patch OK for you? If there's some wrong with your > plan, Pls let me know.
It's fine. > > On Fri, Dec 3, 2010 at 7:42 AM, Edward J. Yoon <[email protected]> wrote: >> +1 !! >> >> On Fri, Dec 3, 2010 at 6:40 AM, Filipe David Manana <[email protected]> >> wrote: >>> Hi all, >>> >>> While thinking about how to implement HAMA-298 (killing a job): >>> >>> - Each task of a user's submitted job is run in a thread >>> (BSPTaskRunner) spawned by a GroomServer. Stopping a thread is >>> something not trivial, and it requires that the thread cooperates. >>> Typically one sets a volatile boolean to true or false, the thread >>> periodically checks it and then *should* stop if it's value changed to >>> true or false. This requires implementers of the class BSP to check >>> for this boolean and possibly adding the same sort of behaviour to >>> BSPPeer. >>> >>> - If a task is simply blocked, for whatever reason, it will never stops. >>> >>> - If we assume users' job code will do this check, we're being too >>> optimistic. >>> >>> Hadoop spawns a new JVM for each task, and the child JVM communicates >>> with the parent (TaskTracker) though the TaskUmbilicalProtocol. This >>> makes it easier to stop a task (simply kill the child process), >>> doesn't require users' job code to periodically check some special >>> boolean, and equally important, allows isolation of errors. >>> >>> I think we should implement the same idea, not only helps implementing >>> a better job kill solution, but it will also be a big +1 for when we >>> support multiple running tasks per GroomServer. >>> >>> If everyone agrees with this, I'll start working on it (it will >>> possibly imply adding much new code). >>> >>> regards, >>> >>> -- >>> Filipe David Manana, >>> [email protected], [email protected] >>> >>> "Reasonable men adapt themselves to the world. >>> Unreasonable men adapt the world to themselves. >>> That's why all progress depends on unreasonable men." >>> >> >> >> >> -- >> Best Regards, Edward J. Yoon >> [email protected] >> http://blog.udanax.org >> > > > > -- > Best Regards, Edward J. Yoon > [email protected] > http://blog.udanax.org > -- Filipe David Manana, [email protected], [email protected] "Reasonable men adapt themselves to the world. Unreasonable men adapt the world to themselves. That's why all progress depends on unreasonable men."
