Built binary is slower than downloaded binary

[Venkatesan Srinivasan]

Hi,

I'm using puppeteer to launch headless chromium and run a bunch of JS on the HTMLs. I noticed that the same JS runs in ~300ms when I use the chromium downloaded from https://storage.googleapis.com/chromium-browser-snapshots/index.html?prefix=Linux_x64/1148123/.

However, if I download the source and build the tag 115.0.5790.102 with the gn args is_debug = false and disable_fieldtrial_testing_config=true it takes ~840ms to finish. I also noticed that the chrome binary size is bigger by ~70mb. Am I missing any other args? Looking for pointers on what could be different.

The files I'm using are here: https://drive.google.com/drive/folders/1j2IGo1tNDTz2iI1l2aVU1zny1giK__SP?usp=sharing 

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Thanks and Regards,

S.Venkatesan

[Christian Biesinger]

You should use `is_official_build = true`.

Christian

[Venkatesan Srinivasan]

The Chromium documentation says "This build requires that you are a Googler with src-internal checked out." Is that just for the branding?

[Nico Weber]

Yes, src-internal is only required for is_chrome_branded = true, not for is_official_build = true.

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[K. Moon]

I do think the practice of using "is_official_build" to mean, "build with optimizations" is confusing, but yes, only Chrome-branded requires internal sources.

You may or may not want to turn off PGO as well. PGO makes the code faster in some cases, but can be a pessimization if your code doesn't match the profile. It also takes a lot longer to build.

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[Nico Weber]

On Wed, Jul 16, 2025 at 9:55 AM K. Moon <km...@chromium.org> wrote:

I do think the practice of using "is_official_build" to mean, "build with optimizations" is confusing, but yes, only Chrome-branded requires internal sources.

You may or may not want to turn off PGO as well. PGO makes the code faster in some cases, but can be a pessimization if your code doesn't match the profile. It also takes a lot longer to build.

(PGO shouldn't affect build times a lot. ThinLTO is what makes official builds take longer.)

 

To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/chromium-dev/CACwGi-7VrGdzidFKSS1pBg571H35hhbQxCu6EP-xB1SHY%2BiRnA%40mail.gmail.com.

[K. Moon]

Good information, thanks! Forgot about the difference.

[Venkatesan Srinivasan]

Thanks folks. "is_official_build" worked. I had to also use "chrome_pgo_phase = 0" and set "sudo sysctl -w vm.max_map_count=262144" as per the documentation.