On Thu, Aug 6, 2009 at 1:12 AM, Jarrod Roberson <jar...@vertigrated.com>wrote:
> > > On Wed, Aug 5, 2009 at 6:04 PM, John Aherne <johnahe...@rocs.co.uk> wrote: > >> >> >> 2. If you have blocking code - *please define blocking* :), then first >> think about putting it into deferToThread with appropriate callbacks and >> return the deferred. As suggested by Jarrod in his response. >> >> >> > blocking code is code that will block or may potentially block the > continued execution of the main reactor thread. > think for the most part long running processes or operations that may be > long running. > doing file or network i/o, calculating cpu intensive work, operations that > may timeout like doing a remote call to another process or host machine, > database operations are usually a culprit, that may be flooded with work or > crashed, the examples go on but are mainly about i/o and cpu intensive > operations. > when these things happen on the reactor / main thread they block the server > from doing anything else, it can't accept new connections, it can't do > anything else until this blocking activity has completed and returned > control to the reactor thread. > > you can handle this without deferToThread by breaking the blocking code up > into smaller pieces sometimes. need to transfer a large file to a socket, > instead of trying to send it all at once send 10KB at a time and yield back > to the reactor and reschedule the next 10KB until finished, this will work, > it might not be the fastest way and still may block for an unacceptable > amount of time on just 10KB, depending on how heavily taxed the i/o system > is at the moment. Usually deferToThread is just easier to implement. > > Jarrod, Thanks. I've incorporated some of what you said into a reply to my own mail. A point I should have added to my other ones first time round. John Aherne > > _______________________________________________ > Twisted-Python mailing list > Twisted-Python@twistedmatrix.com > http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > >
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