I'll try and put all my comments together with the feedback from everyone. Then I can pass it over to the defer documentation thread to see if they are interested in any part of it.
John On Thu, Aug 6, 2009 at 8:02 AM, John Aherne <johnahe...@rocs.co.uk> wrote: > > > 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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