1496146 - Tup build is unusably slow on WSL

Status: RESOLVED WONTFIX

(Firefox Build System :: General, defect)

Description

[(Away)]

I tried to do a (Linux target) WSL build with tup (under WSL's ~/ tree, not /mnt/c), and during the `tup` tier, status lines flew past very quickly up until around 69%, when operations started taking dozens of seconds, even for things like symlinks.

4325) [36.575s] obj-x86_64-pc-linux-gnu/xpcom/build: symlink ../../dist/include/mozilla/Services.h 

`top` shows no significant activity other than `tup`, usually at a little more than 100% of a CPU.

After about 15 minutes I was still only at 71% and killed it.

Comment 1

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

WSL is known[1] to have slow I/O performance... is it possible to analyze whether it's the `top` process spinning vs. waiting on I/O?

[1]: https://github.com/Microsoft/WSL/issues/873

Comment 2

[Gregory Szorc [:gps]]

I'd love to see a profile to see where the time is spent. Could you try using perfmon.exe or UIforETW (https://github.com/google/UIforETW/releases) + Windows Performance Analyzer to see where the time is spent?

I suspect some I/O system calls are being really slow...

Comment 3

[:glob ✱]

Tup is no longer supported.