performance optimization: first steps #307
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BlockIdentifier::getBlockInfo() is one of (or even the most) frequently called functions during map rendering, so it should be fast as possible. but now it is not - it does search on map twice: one for contains() call, and another one on operator[]. this can be easily avoided, and this is obvious optimization.
this is further optimization of BlockIdentifier::getBlockInfo(). there is nothing that requires sorting / specific order, so having map is not really necessary, so hash table will suit better, and it has constant time for element access (what is crucial in there).
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Yes, for larger number of elements a QHash should be much faster than a QMap. And not searching twice is obviously faster. Some time ago we measured performance of different containers (#246). My personal experience is that I do not suffer from rendering performance. I always struggle with file-IO performance (world is stored on network drive). Therefore it is one of my goals to improve file reading, rendering speed was neglected during the last years. |
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first of all, I have no plans to achieve the maximum possible performance or smooth rendering (I'm also fine with delays), I just noticed the "bad place", and think such obvious things must be fixed/optimized, especially when it costs nothing (just a few lines must be changed with no consequences).
I completely agree, code is written in Qt - let's use Qt containers unless there is a strict reason do not so. and those Qt containers may be slower it is expected for me - Qt metaobject system definitely leaves some footprint on performance. |
these 2 commits improve just one function (see its description for details), but the result is impressive - the function became twice faster. and this noticeably affected the whole rendering.
before changes:
after this changes:
and this is what I noticed just looked over the sources... I will look more and likely find more similar prominent places that can be easily optimized. this is just the first step.