Any idea of how much faster we're talking here?
In D130810 the speedup is given as:
Performance linking some programs with --threads=8 (glibc 2.33 malloc and mimalloc):
- clang: 1.05x as fast with glibc malloc, 1.03x as fast with mimalloc
- chrome: 1.04x as fast with glibc malloc, 1.03x as fast with mimalloc
-internal search program: 1.08x as fast with glibc malloc, 1.05x as fast with mimalloc
In D133003 the speedup is given as:
Speed-up with mimalloc and --threads=8 on an Intel Skylake machine:
- clang (Release): 1.27x as fast
- clang (Debug): 1.06x as fast
- chrome (default): 1.05x as fast
- scylladb (default): 1.04x as fast
Speed-up with glibc malloc and --threads=16 on a ThunderX2 (AArch64):
- clang (Release): 1.31x as fast
- scylladb (default): 1.06x as fast
With mimalloc, a medium-sized C++ test repeatedly takes exactly 43.7s to build and link on this system, while with the default allocator it's all over the place from 46s to 49s. I would loosely characterize that as a free 10%.