Comments / metadata in assembly listings don't make sense for code vectorized using Vector API

[Paul Sandoz]

Hi Piotr,

Thanks for the update.

If the 30 iterations are performed from within Java itself I suspect you will see improvements, since the same compilation would not have to be performed every time. But, I dunno if that is within the benchmark rules.

Paul.

> On Jan 30, 2021, at 5:14 AM, Piotr Tarsa <piotr.tarsa at gmail.com> wrote:
> 
> Hi,
> 
> I was busy with other things, so that's why I delayed the reply.
> 
> wt., 19 sty 2021 o 21:17 Paul Sandoz <paul.sandoz at oracle.com> napisał(a):
>> 
>> Hi Piotr,
>> 
>> Thanks for further sharing. I am glad you managed to make progress. I was not aware there were some benchmark rules you needed to adhere to.
> 
> Rules are here:
> https://urldefense.com/v3/__https://benchmarksgame-team.pages.debian.net/benchmarksgame/description/mandelbrot.html*mandelbrot__;Iw!!GqivPVa7Brio!LsQqaL3nuiK_2L-DKtjCpVy_JZKb0yX3_AVdzglYqHMkLO4m6m2o83LEz1lwmQOpVg$ 
> They require bit perfect output and also the same algorithm. Well, in
> the end it's a benchmark of programming languages, not of algorithms.
> 
>> Re: masks, yes there is still work to do for some mask operations.
> 
> OK, good to know.
> 
>> Re: execution from the command line. You can run with -XX:-TieredCompilation (Remi, thanks for the correction in the prior email :-) ), and it's also possible reduce the compilation threshold (at the expense of potentially less accurate profiling information) using say -XX:CompileThreshold=1000 (the default is 10000).
>> It’s always a bit tricky to compare a static (Rust) vs. dynamic system that needs to warm up.
>> 
>> Paul.
> 
> I've tested the provided options, but they don't improve performance
> on the real benchmark:
> 
> $ time for run in {1..30}; do ~/devel/jdk-16/bin/java
> -XX:-TieredCompilation -XX:CompileThreshold=1000 --add-modules
> jdk.incubator.vector -cp
> target/classes/:/home/piotrek/.m2/repository/org/openjdk/jmh/jmh-core/1.27/jmh-core-1.27.jar
> pl.tarsa.mandelbrot_simd_1 16000 > /dev/null; done
> WARNING: Using incubator modules: jdk.incubator.vector
> WARNING: Using incubator modules: jdk.incubator.vector
> ... (repeated for each run)
> WARNING: Using incubator modules: jdk.incubator.vector
> WARNING: Using incubator modules: jdk.incubator.vector
> real 0m42,213s
> user 2m35,740s
> sys 0m4,094s
> 
> $ time for run in {1..30}; do ~/devel/jdk-16/bin/java
> -XX:-TieredCompilation --add-modules jdk.incubator.vector -cp
> target/classes/:/home/piotrek/.m2/repository/org/openjdk/jmh/jmh-core/1.27/jmh-core-1.27.jar
> pl.tarsa.mandelbrot_simd_1 16000 > /dev/null; done
> WARNING: Using incubator modules: jdk.incubator.vector
> WARNING: Using incubator modules: jdk.incubator.vector
> ... (repeated for each run)
> WARNING: Using incubator modules: jdk.incubator.vector
> WARNING: Using incubator modules: jdk.incubator.vector
> real 0m40,038s
> user 2m23,227s
> sys 0m3,515s
> 
> $ time for run in {1..30}; do ~/devel/jdk-16/bin/java --add-modules
> jdk.incubator.vector -cp
> target/classes/:/home/piotrek/.m2/repository/org/openjdk/jmh/jmh-core/1.27/jmh-core-1.27.jar
> pl.tarsa.mandelbrot_simd_1 16000 > /dev/null; done
> WARNING: Using incubator modules: jdk.incubator.vector
> WARNING: Using incubator modules: jdk.incubator.vector
> ... (repeated for each run)
> WARNING: Using incubator modules: jdk.incubator.vector
> WARNING: Using incubator modules: jdk.incubator.vector
> real 0m37,743s
> user 2m16,316s
> sys 0m3,758s
> 
> Looks like the default settings yield best performance. That's a
> positive thing, actually.
> 
> I'll probably send my version to benchmarks game maintainer when he
> switches to Java 16 and then leave tuning to others.
> 
> Thanks for the conversation,
> Piotr
>