Five Projects Selected for SAOC 2019

[Vladimir Panteleev]

On Tuesday, 27 August 2019 at 17:11:33 UTC, Mike Franklin wrote:
> On Tuesday, 27 August 2019 at 12:58:20 UTC, Vladimir Panteleev 
> wrote:
>
>> It will eventually zero in to commit-level accuracy after it's 
>> been running for a while. I cleared the database as the last 
>> time it was running, it was on another CPU, so the timings are 
>> going to be different. (Still need to decide on a way to 
>> measure execution time in some deterministic way.)
>
> If you look at the vibe.d compile-time graph, you'll see 
> there's a 2.5s increase around Mid-2014.  When I zoom in and 
> visit the commit, it's just a DDoc comment change 
> (https://github.com/dlang/phobos/pull/3542).  I don't see how 
> that could account for the large increase in compile time.

The JS part of the project was adopted from somewhere else 
(Mozilla's project for tracking Firefox performance), so it was a 
bit hammered-on to the data schema we use here. Mozilla never 
builds individual successive commits; you have to do it yourself 
to zero in on a specific change. Because of this, the UI was 
confusing and it wasn't obvious whether a commit is actually the 
cause of a change in the metrics.

I've now changed it to only draw a line between two points if 
they're adjacent in the git history. Still not perfect but 
better. You can see this now by zooming into the big change in 
e.g. "Empty program - compilation - peak heap size". (The vibe.d 
one isn't resolved yet, give it a few days.)

The problem with representing this data is that we have the whole 
commit list, which is nice and linear, but not all commits are 
tested, and we can't graph untested commits because they 
effectively don't have an Y value. There's also way too many 
commits to draw at once, so it groups commits that occurred near 
the same time together in one node, which again causes 
complications when it's a mix of tested and untested commits. 
(Currently it uses the median of the test results for tested 
commits.)

More changes:
https://github.com/CyberShadow/TrenD/commits/master