RFR: 8288907: serviceability/jvmti/vthread/SuspendResume1/SuspendResume1.java fails with -XX:TieredStopAtLevel=2,3

[Chris Plummer]

On Thu, 29 Sep 2022 07:21:46 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

> The test SuspendResume fails on linux-aarch64 with timeouts.
> However, it never fails when test timeout is set to a bigger value:
> 
> diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume1/SuspendResume1.java b/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume1/SuspendResume1.java
> index cd5b8251fce..562f2eae921 100644
> --- a/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume1/SuspendResume1.java
> +++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume1/SuspendResume1.java
> @@ -29,7 +29,7 @@
>   * @library /test/lib
>   * @compile --enable-preview -source ${jdk.version} SuspendResume1.java
>   * @run driver jdk.test.lib.FileInstaller . .
> - * @run main/othervm/native
> + * @run main/othervm/native/timeout=600
>   *      --enable-preview
>   *      -Djava.util.concurrent.ForkJoinPool.common.parallelism=1
>   *      -agentlib:SuspendResume1
> 
> 
> I'd like to push this as a trivial fix.
> 
> Testing: Submitted mach5 test runs on multiple platforms.

I'm not so sure increasing the timeout is the right thing to do. Here are the results of running 5 times on each of our 5 platforms with `-XX:TieredStopAtLevel=2"`

macosx-aarch64-debug		22s
windows-x64-debug			23s
windows-x64-debug			23s
macosx-aarch64-debug		23s
macosx-aarch64-debug		24s
macosx-aarch64-debug		24s
windows-x64-debug			24s
macosx-x64-debug			24s
macosx-aarch64-debug		25s
macosx-x64-debug			26s
macosx-x64-debug			26s
macosx-x64-debug			26s
macosx-x64-debug			26s
windows-x64-debug			28s
windows-x64-debug			33s
linux-x64-debug				43s
linux-x64-debug				45s
linux-aarch64-debug			2m 17s
linux-x64-debug				2m 20s
linux-x64-debug				2m 42s
linux-x64-debug				2m 59s
linux-aarch64-debug			3m 22s
linux-aarch64-debug			4m 31s
linux-aarch64-debug			6m 30s
linux-aarch64-debug			9m 22s

The last one was a timeout. So it seems that linux-aarch64 is consistently slow. linux-x64 is also a bit slow in some cases.  It seems it would be worth understanding these performance differences.

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PR: https://git.openjdk.org/jdk/pull/10480