Oh, Is HAMA-331 patch OK for you? If there's some wrong with your plan, Pls let me know.
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
