From: Karthik Nayak <karthik.188@gmail.com>
Date: Wed, 30 Sep 2026 12:20:00 GMT
Subject: Re: [PATCH 3/7] meson: use precompiled headers for our test-helper
Message-ID: <CAOLa=ZRdeuYTv4f-1EEJmF+Dp76kDvz5+dWNkmnuMDjipDyV5w@mail.gmail.com>
In-Reply-To: <20260924-pks-meson-improvements-v1-3-90b7f79f1c4e@pks.im>

Patrick Steinhardt <ps@pks.im> writes:

> In 671df48df8 (meson: precompile "git-compat-util.h", 2026-03-19) we
> have introduced support for precompiled headers into Meson. At that time
> though we only converted "libgit.a" to make use of those.
>
> Nowadays though, our test-helper also consists of a bunch of code files,
> and all of these include "git-compat-util.h" via "test-tool.h" as the
> first header. So they're a natural target to also use precompiled
> headers.
>
> Adapt the test-tool executable to make use of them, which results in a
> surprisingly large speedup for clean builds:
>
>   Benchmark 1: meson compile (version = HEAD~)
>     Time (mean ± σ):      6.363 s ±  0.033 s    [User: 92.858 s, System: 22.500 s]
>     Range (min … max):    6.311 s …  6.418 s    10 runs
>
>   Benchmark 2: meson compile (version = HEAD)
>     Time (mean ± σ):      5.327 s ±  0.021 s    [User: 75.135 s, System: 20.373 s]
>     Range (min … max):    5.299 s …  5.362 s    10 runs
>
>   Summary
>     meson compile (version = HEAD) ran
>       1.19 ± 0.01 times faster than meson compile (version = HEAD~)
>
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  t/helper/meson.build | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/t/helper/meson.build b/t/helper/meson.build
> index 3235f10ab8..ae513b4cdc 100644
> --- a/t/helper/meson.build
> +++ b/t/helper/meson.build
> @@ -83,6 +83,7 @@ test_tool_sources = [
>
>  test_tool = executable('test-tool',
>    sources: test_tool_sources,
> +  c_pch: '../../tools/precompiled.h',
>    dependencies: [libgit_commonmain],
>  )
>  bin_wrappers += test_tool
>

Seems like a straightforward win. Nice to see.

> --
> 2.56.0.rc2.329.gd58861e689.dirty