Well, I did a bit of programming this morning before work, and on the way driving to work I had one of those "Wait a second..." moments. Here's the guilty section of code:
private void GenerateMapFromGraph(MapNode current, Map map, Point seam, ParenthoodChain parentChain)
{
if (current.Generated)
return;
current.Generated = true;
bool placed = false;
System.Console.WriteLine(string.Format("Generating {0} - {1}", current.Type.ToString(), current.UniqueID.ToString()));It's that last line that got me. It was some debugging code that I forgot to remove. This function gets called recursively during map generation, a huge number of times and writing to stdout is very slow.
Some baseline numbers (release mode attached to debugger) in generating 100 maps gives me:
- Before - 47473ms
- After - 1041ms
The lesson for today, next time performance is terrible, check stdout to make sure you aren't dumping 10000 lines of text to it during map generation.
Update: Now I just need to find some crazy optimization for my cave map generator and I can get rid of my "loading" screen, since I can generate 100 of the stitch levels in about a second.
3 comments:
Amen to that! I once made my map generator display a line on stdout for each map cell visited by some sort of recursive function too. My maps are 112x90 and each cell got visited several times. It took ages to generate even a single map. Duh!
I wonder if you have a profiler. This is the kind of thing that can easily be detected with one, it really helps focus optimization efforts. I remember using one to identify where an infinite loop in a parser a few years ago.
I actually did use a profiler EQATEC's one for .NET. The issue that for some reason the System.Console stuff wasn't showing up clearly. I'm not sure if they scrub out system calls or what, but i figured it'd be obvious in a profiler but it wasn't.
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