Extremely slow Petrel import + crash when saving

Jef Driesen jefdriesen at telenet.be
Fri Sep 20 13:30:04 UTC 2013

On 20-09-13 20:34, Henrik Brautaset Aronsen wrote:
> Jef Driesen wrote:
>> Can you try the attached patch on your mac? Because sending data
>> appears to be the problem, sending the packet byte by byte is
>> certainly not going to be the fastest. With the attached patch, the
>> packet is send at once.
>> Another thing that's worth looking at are the tcdrain calls in
>> serial_write. Just add some extra WARNING or INFO between the write
>> and tcdrain. I wonder if it's the write or the tcdrain which taking
>> most of the time.
> Massive improvement!   The whole download process took 4.5 minutes,
> that's about 4.7 seconds per dive.  Thanks a lot!

 From 40 to 4.5 minutes. That's no doubt a very nice improvement!

I assume the overhead of sending a single byte or an entire packet remained 
roughly the same. So by sending the entire packet at once, you get a speed 
increase proportional to the length of the packet. I'm still surprised sending a 
byte/packet is in the order of seconds instead of milliseconds. But at the least 
the download speed is now acceptable.

Could you do me a favor, and do a testrun with the attached patch applied, and 
the previous one (temporary) reverted? And then send me the logfile. I would 
like to have a look at the timings of the write vs tcdrain calls to get a better 
understanding of what might be going on. I just need a few packets, so you can 
cancel the download after a minute or so. If you still have it, I'm also 
interested in the logfile of your fast download.

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