Re: [Flightgear-devel] Re: opening window & splash screen

[James Turner]

On 5 May 2005, at 09:18, Melchior FRANZ wrote: Oh. I hope you mean that the startup time has become much too long over time, and not that this patch made it worse. I don't think that the patch has a noticable effect, neither positive nor negative. Except that it possibly improves the perception and makes it feel a bit faster. And that will further improve with progress info. What has slowed down fgfs in the last time was the migration to the new database formats -- not because they are read less effectively, but simply because they contain much more data. That's at least the impression that I got from valgrind (http://www.valgrind.org/) runs. I don't have much time to delve into this right now (hah!), but I have some log calls in my local build, which have been fairly consistent (haven't tested since your changes, Melchior - when I do, I'll post those numbers). That said, here are the numbers I have (for three runs)              time to run  fgMainInit:     44 sec     32 sec     29 sec time between idle_state 0 and idle_state 1000      33 sec     10 sec     10 sec (wall-clock) time after hitting idle_state 1000  before scene appears     consistently about 25 - 30 seconds Comments - the first phase (lots of database traversal) is obviously very dependant on file system cache hot-ness, and the second phase similarly. The third phase, *after* idle-state 1000, is the bit I was referring to when I talked about starvation; while it's doing this wait, I see the splash screen, and see log output from subsystems frequently (traffic manager, clouds, ephemeris), but it seems to sit there for ages before showing the cockpit + scenery. I ran a statistical profiler on the startup, and it didn't get all the way through startup before it hit it's log size limit, but the first part was spending huge amounts of time parsing data files, especially doing string - to float parsing. Doing the equivalent of 'atof' was something like 11% of the total time for the profile I ran. Lazyness is the way to go here, I'd suggest. Or binary file formats. James -- Ignorance more frequently begets confidence than does knowledge.

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