In our efforts to migrate from Java 6 (u39) to Java 8 (u51), we were faced with the problem of a longer warm-up for Java 8 compared to 6.
We noticed this both with the test run of the performance test and with the initial queries when starting Tomcat 7 (u35) with Java 8.
We are working on a 64-bit Linux Redhat system.
Sorry, I do not have an isolated test case.
As for the performance testing program, I found that Java 6 approached stable operation of about 215 milliseconds in 10 iterations, while Java 8 took 800 milliseconds after 10 iterations and required 70 iterations up to 215 ms.
When we ran JMeter tests on concurrency out of 10 on our tomcat webapp (with Spring 2.5, jackson, xerces XML parser, jedis, etc.) immediately after restarting Java 6, it took less than a minute to give while Java 8 took about 5-6 minutes and was slower by several orders of magnitude until this time.
Disabling multilevel compilation using -XX: -TieredCompilation The VM HotSpot option in Java 8 fixed the warming up problem with a performance testing program without changing stability. This is surprising since Tiered Compilation actually involves accelerating warm-up.
However, turning off tiered compilation did not produce a similar improvement in warm-up time for the Tomcat server.
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