[ISSUE] foot: Add PGO build option

[ISSUE] foot: Add PGO build option

[travankor]

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New issue by travankor on void-packages repository

https://github.com/void-linux/void-packages/issues/29526

Description:
[PGO optimization](https://codeberg.org/dnkl/foot/src/branch/master/doc/benchmark.md) speed foot up by a significant amount. Add a build option that [enables PGO ](https://codeberg.org/dnkl/foot/src/branch/master/INSTALL.md#user-content-partial-pgo) during build.

Re: foot: Add PGO build option

[ericonr]

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New comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/issues/29526#issuecomment-828031140

Comment:
Definitely not on by default, since PGO is affected by the CPU that's being used.

Re: foot: Add PGO build option

[dnkl]

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New comment by dnkl on void-packages repository

https://github.com/void-linux/void-packages/issues/29526#issuecomment-872740075

Comment:
> since PGO is affected by the CPU that's being used.

It's actually not. PGO counts functions and branches executed, and helps re-organize the code; it clusters "hot" functions, to improve cache locality. It can also re-arrange code within a function to make the "normal" path the fast path (i.e. placing the not-often executed branches at e.g. the end of the function). But PGO in itself does not emit CPU specific instructions, nor does it depend on CPU-specific knowledge for e.g. instruction scheduling.

Over at nix, @sternenseemann has been able to do reproducable PGO builds. That is, builds on different systems produce identical output. I can't for my life find the issue, or comment, where I saw this, but pretty sure sterni can fill in the details, if needed.

Oh, and as a bonus, PGO builds tend to be smaller (in binary size) than regular release builds. This is _at least_ true for LTO builds (which I strongly recommend building foot with, with or without PGO).

Re: foot: Add PGO build option

[sternenseemann]

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New comment by sternenseemann on void-packages repository

https://github.com/void-linux/void-packages/issues/29526#issuecomment-872803985

Comment:
I can configure that building foot with PGO can be reproducible, i. e. I can reproduce the exact hash of the binary package produced by our builders on two different local machines (at different times). This also leads me to [believe that a reproducible gcc with PGO is possible](https://github.com/NixOS/nixpkgs/pull/112928#issuecomment-809336063), but most likely very hard to get to work.

The only thing necessary to achieve a reproducible foot build is generating the random inputs which are used for profiling while building using a [fixed seed](https://github.com/NixOS/nixpkgs/blob/43b257365c2c73fc31421e9b28dde1166d75506a/pkgs/applications/terminal-emulators/foot/default.nix#L62).

Re: foot: Add PGO build option

[sternenseemann]

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New comment by sternenseemann on void-packages repository

https://github.com/void-linux/void-packages/issues/29526#issuecomment-872803985

Comment:
I can confirm that building foot with PGO can be reproducible, i. e. I can reproduce the exact hash of the binary package produced by our builders on two different local machines (at different times). This also leads me to [believe that a reproducible gcc with PGO is possible](https://github.com/NixOS/nixpkgs/pull/112928#issuecomment-809336063), but most likely very hard to get to work.

The only thing necessary to achieve a reproducible foot build is generating the random inputs which are used for profiling while building using a [fixed seed](https://github.com/NixOS/nixpkgs/blob/43b257365c2c73fc31421e9b28dde1166d75506a/pkgs/applications/terminal-emulators/foot/default.nix#L62).

Re: foot: Add PGO build option

[github-actions]

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New comment by github-actions[bot] on void-packages repository

https://github.com/void-linux/void-packages/issues/29526#issuecomment-1120562442

Comment:
Issues become stale 90 days after last activity and are closed 14 days after that.  If this issue is still relevant bump it or assign it.

Re: foot: Add PGO build option

[ericonr]

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New comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/issues/29526#issuecomment-1121827542

Comment:
Not stale. @ifreund do you have anything in effect for this? I think I had a branch attempting it a while back

Re: foot: Add PGO build option

[ifreund]

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New comment by ifreund on void-packages repository

https://github.com/void-linux/void-packages/issues/29526#issuecomment-1122249554

Comment:
@ericonr nope, I haven't tried to implement this yet.

Re: foot: Add PGO build option

[github-actions]

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New comment by github-actions[bot] on void-packages repository

https://github.com/void-linux/void-packages/issues/29526#issuecomment-1208832543

Comment:
Issues become stale 90 days after last activity and are closed 14 days after that.  If this issue is still relevant bump it or assign it.

Re: [ISSUE] [CLOSED] foot: Add PGO build option

[github-actions]

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Closed issue by travankor on void-packages repository

https://github.com/void-linux/void-packages/issues/29526

Description:
[PGO optimization](https://codeberg.org/dnkl/foot/src/branch/master/doc/benchmark.md) speed foot up by a significant amount. Add a build option that [enables PGO ](https://codeberg.org/dnkl/foot/src/branch/master/INSTALL.md#user-content-partial-pgo) during build.