motiejus/test-zig-cc
1
Fork 0
Code Releases Activity

let it be so

Browse Source
This commit is contained in:
Motiejus Jakštys
2022-10-19 11:35:55 +03:00
commit 64a3ef606e
8 changed files with 171 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
README.md Normal file
View File

@@ -0,0 +1,35 @@
bazel-zig-cc and llvm
---------------------
bazel-zig-cc has a performance issue when compiling many files. This repository
reproduces that.
Steps to reproduce
------------------
llvm14: 10-11 seconds to compile 96 binaries on an 8-core machine:
```
$ bazel clean; bazel shutdown; bazel build --extra_toolchains=@llvm_toolchain//:cc-toolchain-x86_64-linux ...
INFO: Starting clean (this may take a while). Consider using --async if the clean takes more than several minutes.
Starting local Bazel server and connecting to it...
INFO: Analyzed 96 targets (41 packages loaded, 1458 targets configured).
INFO: Found 96 targets...
INFO: Elapsed time: 10.725s, Critical Path: 0.66s
INFO: 481 processes: 289 internal, 192 linux-sandbox.
INFO: Build completed successfully, 481 total actions
```
zig cc: 3.5 minutes. Anecdotally when looking at `htop` looks like it does not
parallelize at all:
```
$ bazel clean; bazel shutdown; bazel build --platforms=@zig_sdk//libc_aware/platform:linux_amd64_gnu.2.28 ...
INFO: Starting clean (this may take a while). Consider using --async if the clean takes more than several minutes.
Starting local Bazel server and connecting to it...
INFO: Analyzed 96 targets (41 packages loaded, 14394 targets configured).
INFO: Found 96 targets...
INFO: Elapsed time: 214.333s, Critical Path: 18.31s
INFO: 385 processes: 193 internal, 192 linux-sandbox.
INFO: Build completed successfully, 385 total actions
```