RFR: 8298920: Improve microbenchmark build times

[Daniel Jeliński]

On Fri, 16 Aug 2024 12:24:19 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

> Currently incremental builds for the microbenchmarks may take notable amount of time, like:
> 
> $ touch test/micro/org/openjdk/bench/java/io/BlackholedOutputStream.java; time make test TEST=jaxp:tier1
> Building target 'test' in configuration 'linux-x86_64-server-release'
> Compiling up to 656 files for BUILD_JDK_MICROBENCHMARK
> Running Indify on microbenchmark classes
> [snip]
> ==============================
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR
>    jtreg:test/jaxp:tier1                                 0     0     0     0
> ==============================
> TEST SUCCESS
> 
> Finished building target 'test' in configuration 'linux-x86_64-server-release'
> 
> real    0m37,581s
> user    2m4,747s
> sys     0m7,223s
> 
> 
> The microbenchmark compilation is not using the `Depend` plugin that avoids recompilation of other files if the change files only contain minor changes (i.e. non-API changes). The patch here proposes to enhance the build to use the `Depend` plugin. The change that enables that is `CREATE_API_DIGEST := true,`, but since both the `Depend` plugin and JMH framework needs to be added to the classpath the patch re-organizes the code a little to properly augment the classpath.
> 
> With this patch, a build similar to the above might be:
> 
> $ touch test/micro/org/openjdk/bench/java/io/BlackholedOutputStream.java; time make test TEST=jaxp:tier1
> Building target 'test' in configuration 'linux-x86_64-server-release'
> Compiling up to 656 files for BUILD_JDK_MICROBENCHMARK
> Running Indify on microbenchmark classes
> [snip]
> ==============================
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR
>    jtreg:test/jaxp:tier1                                 0     0     0     0
> ==============================
> TEST SUCCESS
> 
> Finished building target 'test' in configuration 'linux-x86_64-server-release'
> 
> real    0m7,505s
> user    0m14,128s
> sys     0m3,158s

That's a great improvement. Thanks!

I noticed that with these changes, the api files (_the.BUILD_JDK_MICROBENCHMARK_*api) are included in the resulting jar file (images/test/micro/benchmarks.jar). Probably not a big deal.

> Note that this is affecting regular jtreg tests too. So great fix.

Yeah! Though I tend to keep a worktree configured without --with-jmh for even greater speedup.

-------------

Marked as reviewed by djelinski (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/20616#pullrequestreview-2246339529