java tink library is not scaling with java threads

[uploeger]

It seems that java tink library does not scale with java threads. Find attached a small java test program.

Find below test results with one and three threads, running on a unix (redhat) box with 24 vCPUs.

In both cases around 1.000.000 encryption operations are executed every second. The amount of encryption operations is not increasing when using more threads.

java AeadThread encrypt "This is a test" 10000000 1
origtext: This is a test
Thread: 1 for encryption loop: Mon Jun 12 10:49:25 CEST 2023
Thread: 1 after encryption loop: Mon Jun 12 10:49:34 CEST 2023

java AeadThread encrypt "This is a test" 10000000 3
origtext: This is a test
Thread: 2 for encryption loop: Mon Jun 12 11:09:25 CEST 2023
Thread: 3 for encryption loop: Mon Jun 12 11:09:25 CEST 2023
Thread: 1 for encryption loop: Mon Jun 12 11:09:25 CEST 2023
Thread: 1 after encryption loop: Mon Jun 12 11:09:53 CEST 2023
Thread: 2 after encryption loop: Mon Jun 12 11:09:53 CEST 2023
Thread: 3 after encryption loop: Mon Jun 12 11:09:53 CEST 2023

test environment:
java version: openjdk version "1.8.0_362"
java tink library version: 1.9.0

Aead object is shared between threads.

AeadThread.zip

[tholenst]

This seems to be a duplicate of https://github.com/google/tink/issues/696. Please reply on my comments there.