I absolutely did not mean to imply that you did a bad job at any point, or to discourage you. The mere fact that you reached that far into the game’s internals, achieved the speedup you were aiming for, and left it completely functional is extremely impressive to me.
And that’s part of why I’m confused. If you’d screwed up the profiling in some obvious way, I’d have chalked it up to bad profiling and been perfectly unconfused. But your methods are good as far as I can see, and with the detail you’ve gone into I feel I see sufficiently far. Also, well, whatever you did, it evidently did help. So the question of what the hell is happening is all the more poignant.
(I agree with the other commenter that you may have dismissed WaitForSingleObject too quickly—can your tools give you flame graphs?.. In general, though, if machine code produced by an optimizing compiler takes a minute on a modern machine—i.e. hundreds of billions of issued instructions—to process data not measured in gigabytes, then something has gone so wrong that even the most screwed-up of profiling methodologies shouldn’t miss the culprit that much. A minute of work is bound to be a very, very target-rich environment, enough so that I’d expect even ol’ GDB & Ctrl-C to be helpful. Thus my discounting the possibility that your profiling is wrong.)
And that’s part of why I’m confused. If you’d screwed up the profiling in some obvious way, I’d have chalked it up to bad profiling and been perfectly unconfused. But your methods are good as far as I can see, and with the detail you’ve gone into I feel I see sufficiently far. Also, well, whatever you did, it evidently did help. So the question of what the hell is happening is all the more poignant.
(I agree with the other commenter that you may have dismissed WaitForSingleObject too quickly—can your tools give you flame graphs?.. In general, though, if machine code produced by an optimizing compiler takes a minute on a modern machine—i.e. hundreds of billions of issued instructions—to process data not measured in gigabytes, then something has gone so wrong that even the most screwed-up of profiling methodologies shouldn’t miss the culprit that much. A minute of work is bound to be a very, very target-rich environment, enough so that I’d expect even ol’ GDB & Ctrl-C to be helpful. Thus my discounting the possibility that your profiling is wrong.)