Add ThreadCount type

[wendigo]

No description provided.

[wendigo]

cc @martint @electrum @hashhar @phd3

[electrum]

We definitely do not want to add OSHI as a dependency here. Can we do this in pure Java, such as by reading /proc/cpuinfo?

[wendigo]

@electrum can I make it optional with the default being a /proc/cpuinfo based?

[electrum]

Optional dependencies are a pain. How do you test that the fallback works? You need a different test suite that doesn’t have the optional dependency on the classpath.

The question is if we can get this from Java without needing a native dependency. If no, then we can evaluate options. If yes, then why make it optional?

[wendigo]

@electrum Sure. I'll implement it without deps. Thanks for guidance!

[wendigo]

@electrum ptal

[wendigo]

Tested in docker on arm64:

public static void main(String[] args)
    {
        System.out.println("Exact value of " + ThreadsCount.valueOf(args[0]));
        System.out.println("Next 2th value of " + ThreadsCount.valueOf(args[0]).nextPowerOf2());
    }

ARG JAVA_VERSION=17
FROM openjdk:${JAVA_VERSION}-jdk

COPY target/units-1.9-SNAPSHOT.jar units.jar
COPY *.jar .

ENTRYPOINT ["java", "-cp", "units.jar:slf4j-api-2.0.6.jar", "io.airlift.units.ThreadsCount"]
CMD [""]

❯ docker run --platform=linux/amd64 --cpus=3.5 threads-count 0.5C
Exact value of 2 threads
Next 2th value of 2 threads
❯ docker run --platform=linux/amd64 --cpus=3.5 threads-count 1C
Exact value of 4 threads
Next 2th value of 4 threads
❯ docker run --platform=linux/amd64 --cpus=3.5 threads-count 1.2C
Exact value of 5 threads
Next 2th value of 8 threads
❯ docker run --platform=linux/amd64 --cpus=3.5 threads-count 3C
Exact value of 12 threads
Next 2th value of 16 threads
❯ docker run --platform=linux/amd64 --cpus=1.5 threads-count 1C
Exact value of 2 threads
Next 2th value of 2 threads
❯ docker run --platform=linux/amd64 --cpus=1.5 threads-count 2C
Exact value of 4 threads
Next 2th value of 4 threads
❯ docker run --platform=linux/amd64 --cpus=8 threads-count 2C
Exact value of 16 threads
Next 2th value of 16 threads
❯ docker run --platform=linux/amd64 --cpus=8 threads-count 1.4C
Exact value of 11 threads
Next 2th value of 16 threads

[electrum]

Looking good

[wendigo]

@electrum all of your comments are addressed now

[wendigo]

I've fixed the compilation error on JDK 11 (the last working airlift version is 219, 220 was switched to JDK 17)

[wendigo]

@sopel39 ptal

[losipiuk]

LGTM - but I @sopel39 PTAL too.

[wendigo]

@dain @electrum please review. I've dropped powerOfTwo on ThreadCount

[electrum]

Let's drop the @PowerOfTwo validator. If we're going to do the clamping in the caller, then it doesn't make sense to have this validator. Also, it wouldn't work with ThreadCount since that isn't an integer.

[wendigo]

@electrum PTAL. Rebased and addressed all comments. I've added @MinThreadCount and @MaxThreadCount validators