Performance differences between Windows and Linux

[jmather-sesi]

I've been running our software through our benchmark suite with both mimalloc 1.8.7 and mimalloc 2.1.7 and have noticed some differences in its behaviour across OSes. On Windows, 2.1.7 pretty much always comes out on top in speed, vsize and rss. However on Linux, it's a bit more complicated. In some tests, I've seen 2.1.7 consume up to 75% more virtual memory than 1.8.7. rss is generally the same between both versions.

I'm wondering if this has been seen before, and if there's anything we can do about it. Ideally we'd like to use the same allocator on both OSes as its less to maintain. We need to be cautious about our virtual memory size as some users monitor the vsize as a way to detect swapping, and will kill the process if vsize exceeds the amount of physical memory.