Likely because it's easier to test against different allocators with a small replay tool than it is to try and get Doom3 to compile against dlmalloc, jemalloc, mimalloc, rpmalloc and tlsf.
timedemo <demo file> uscache
The DOOM3 source is here https://github.com/id-Software/DOOM-3
There are lots of facilities for recording and playing back demos. The author could record their own gameplay and play it back in realtime vs running timedemo (which plays back as fast as possible).
https://github.com/id-Software/DOOM-3/blob/master/neo/framew...
2865: cmdSystem->AddCommand( "recordDemo", "records a demo" );
2866: cmdSystem->AddCommand( "stopRecording", "stops demo recording" );
2867: cmdSystem->AddCommand( "playDemo", "plays back a demo",
2868: cmdSystem->AddCommand( "timeDemo", "times a demo",
2869: cmdSystem->AddCommand( "timeDemoQuit", "times a demo and quits",
id Tech games have "timedemo" mode, where they replay a pre-recorded demo as fast as possible, and report how many FPS it was able to process. These were very popular benchmarks long ago.