2009/8/19 Robert Bradshaw <rober...@math.washington.edu>: > > On Wed, 19 Aug 2009, William Stein wrote: > >> >> On Wed, Aug 19, 2009 at 1:19 AM, Robert >> Bradshaw<rober...@math.washington.edu> wrote: >>> Multithreading will have to be introduced at one >>> level or another to scale the notebook to more than a single >>> processor anyways. >>> >>> - Robert >> >> Huh? Why? I don't see any need for multithreading to solve the >> above problem, or rather I don't understand what problem you're >> talking about. The notebook already scales to more than a single >> processor. > > I am talking about the case where there are enough users that the notebook > process itself becomes the bottleneck. It all depends on how lightweight > the shuffling data between the underlying processes and the browser is, > and how many concurrent users one wants to support for a single notebook. > In the asynchronous model there is only one thread handling all of the > connections. (Also, anything long-running, e.g. taring up all a users > worksheets for download, needs to spawn a separate thread/process.) > > Of course if the whole setup is running on a single machine, it may be > that the computational processes are always the bottleneck.
Thanks for the clarification, which makes sense. There are other approaches. If one had tens of thousands of simultaneous users, instead of having multiple threads one could assign users to a separate process (that could handle up to n users max) when they first connect. That could scale better than SMP threads, since it is easier to distribute the load across servers. Maybe this is just orthogonal though. Regarding the tar example, one solution might be to run it as a separate process, then later check if that process finished -- it is not necessary for the notebook server process to wait for a subprocess doing tar to finish before continuing. Another possibility if the tar'ing happens in the same process would be to use fork. For fun, I just looked at Activity Monitor on OS X, and sorted the tasks I'm running by number of threads. The top is Firefox and the bottom is python. -- William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
