Hi Matt. My apologies, I was away a good part of the day and evening today. Here are the numbers for the different methods:
original os.system call: 29.685759 s buffered stdout call: 213.370982 s (with 1mb buffer) direct to stdout call: 33.378756 s The second method worked great and is essentially equivalent in execution time to original call :-). This has got me smiling. Many thanks Matt for your help, particularly working through the second example that provided equivalent speed. Regards, David David Pratt wrote: > Hi Matt. Many thanks. Sorry I had not seen your second post. I'll give > this a try and time the completion to compare the differences and post > back later today to show os.system, buffered imput and using a file > directly for stdout. > > Regards, > David > > Matt Nordhoff wrote: >> David Pratt wrote: >>> Hi David and Matt. I appreciate your help which has got me moving >>> forward again so many thanks for your reply. I have been using >>> subprocess.Popen a fair bit but this was the first time I had to use >>> subprocess to capture large file output. The trouble I was having was >>> with the process would just hang. Chunking was the solution. I guess I >>> assumed this would be taken care of in the internals. >>> >>> Overall, I wish subprocess had some better documentation since it is >>> definitely not a drop in replacement for os.system. In other >>> circumstances I am using subprocess.call() for simple calls which works >>> fine. >>> >>> The speed of this solution is slower than os.system. Would a queue of >>> some kind be needed to speed this up? Has anyone implemented something >>> like this? Many thanks. >>> >>> Regards, >>> David >> Did you see my second message? That should help performance. If not, I'm >> totally out of my depth and have no idea at all. Sorry. >> >> (How much slower? 10%? 200%?) -- http://mail.python.org/mailman/listinfo/python-list
