Any way to speed up on the fly build?

[olstakh]

Hi. Our benchmark project (latest version) references few heavy projects, so around a few dozen projects are in the graph, but running benchmarks triggers on the fly build that takes ~40 minutes. We had to increase the default build timeout parameter for the job. What are the best practices for not having this absurd amount of build time? I can't easily create a repro for this to share, since it'll be quite involved process, just looking for overall best practices or configs that i can try. At this point the build is longer than the run itself :)

[timcassell]

Are you benchmarking NativeAOT? The builds for that are known to take a very long time.

[olstakh]

@timcassell no, just regular managed projects. Although some of the references are xunit.v3 projects, which do produce self-contained executables, but i wouldn't think it matters much

[olstakh]

Basically the whole solution is building in 15 minutes on a bad day, but subset of that builds for 40+ minutes during benchmark runs, which is confusing

[filzrev]

Basically the whole solution is building in 15 minutes on a bad day, but subset of that builds for 40+ minutes during benchmark runs, which is confusing

BenchmarkDotNet build auto-generated project with /p:UseSharedCompilation=false option.

So it's expected be slower compared to normal build.
Though, it seems build time is increasing too much and it might there is another reason that slowdown build.

It it able to take MSBuild binlog and what MSBuild phase taking times?

[olstakh]

For a small repro (where regular build takes 4.5 minues, but on the fly build takes 15 minutes) - seems to be just compilation is expensive

I'll try to get binlog for 40-minutes one that i mention in the OP, although i'm assuming the picture will be the same

[filzrev]

From screenshot.

It looks like same project are built multiple times. (Incremental build is not used as expected)
Because the DoubleWrites section exists.

Is it able to resolve DoubleWrites files issue and compare binlog results?