My Benchmark Was 4x Wrong Because of WSL
Launching the server with its working directory on /mnt/c cost ePHPm about 4x on a light workload. The report built a wrong explanation on top of it, and the strace shows why.
I do most of my benchmarking on a Windows box in WSL2. It’s the machine on my desk with 32 threads and 62 GB of RAM.
Everybody who does that learns the first rule early: don’t put your data on /mnt/c. DrvFs is the 9p-backed mount that
exposes the Windows drives inside WSL, and it’s slow for file-heavy work. So the databases, the docroot and the build
output all live on the WSL ext4 disk. My scaling harness for ePHPm even says so in
capital letters in its README.
