Re: [PATCH 8/8] mm: enable maple tree RCU mode by default.

Matthew Wilcox
2023-04-11T02:25:42Z

On Tue, Apr 11, 2023 at 09:25:16AM +0800, kernel test robot wrote:
> kernel test robot noticed a -8.5% regression of stress-ng.mmapaddr.ops_per_sec on:

Assuming this is the test in question:

https://github.com/ColinIanKing/stress-ng/blob/master/stress-mmapaddr.c

then yes, this is expected. The test calls mmap() and munmap() a lot,
and we've made those slower in order to fix a bug.

While it does take pagefaults (which is a better test than some
microbenchmarks), it only takes one pagefault per call to mmap() and
munmap(), which is not representative of real workloads.

Thanks for running the test.