DMD Performance Regression Publisher [GSoC 2026]

[user1234]

On Friday, 12 June 2026 at 18:58:03 UTC, Abul Hossain Khan wrote:
> Hi everyone,
> I am working on the Performance Regression Publisher project 
> under the mentorship of Dennis.
>
> My progress so far: the initial end-to-end pipeline has been 
> built and is working on my fork. The bot builds DMD at a PR's 
> merge-base and at its head, measures a small set of metrics 
> under cachegrind, and posts a single sticky comment with the 
> diff.

This is very good work. the CI aspects have been a bit left aside 
since a few years, but while the initial impact is awesome (I 
daily check what's going on on GH for DMD, and others..) I have a 
few questions.

1. how is this reliable ?

Are you sure that the hardware used is always the same, i.e when 
testing master vs head.

2. How the metric is relevant ?

Is a PR always supposed to lower the cost in term of intruction 
refs ? This project put a bit of pressure in this that a new 
feature will look like a regression.

3. Ecological cost

That pumps energy, is that worth ?