Performance loss with word count benchmark

[Matthew Wilcox]

On Thu, Sep 28, 2023 at 06:32:01PM +0200, Julia Lawall wrote:
> https://github.com/kozyraki/phoenix
> 
> The test is in phoenix-2.0
> 
> It can be run as
> 
> tests/word_count/word_count word_count/word_count_datafiles/word_100MB.txt
> 
> I think you have to download the word_100MB.txt file separately.

Thanks, Julia.  Bringing in some other people that care about maple tree
performance.

A quick glance at strace doesn't show much in the way of calls to mmap.
Using strace -f to make sure I capture all the threads shows a lot of
anon mmap calls, but mostly of 41 and 81 pages in length (164kB, 324kB).
That might be a libc malloc artefact?

Ooh, just found one that's 161 pages.  But there are a lot of calls to
mprotect; that's going to create new VMAs, right?