RFR: 8353718: Improve droppingMessage test in async UL tests [v2]

[David Holmes]

On Fri, 4 Apr 2025 13:52:28 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> Hi,
>> 
>> The test for dropping messages have started to fail on aarch64 fast debug on Linux only. It's currently unclear why this occurs. To figure out why, I've extended the test to do emit more diagnostic information if it fails.
>> 
>> 1. Fail if the asynchronous mode isn't "drop" (the test makes no sense with stalling mode)
>> 2. Print the entirety of the log file produced if no missing messages are found
>> 3. If the thread running the test is unattached, then async UL will emit log messages in synchronous mode. Therefore, if the thread is unattached, the test now fails with an error message.
>> 
>> With these changes integrated, I hope to be able to find the actual culprit of this bug.
>> 
>> I have attempted to reproduce this bug on both mainline and with this patch, but I have been unable to do so.
>
> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Do not use BufferUpdater

I'm not following some of your changes sorry, and it is unclear whether these are intended to be permanent or temporary adjustments to the test in places. ??

test/hotspot/gtest/logging/test_asynclog.cpp line 81:

> 79: 
> 80:     // shrink async buffer.
> 81:     //AsyncLogWriter::BufferUpdater saver(1024);

You have some comments that no longer apply once you comment this out. It is also unclear why you are commenting it out and not just deleting it.

test/hotspot/gtest/logging/test_asynclog.cpp line 87:

> 85:     // write more messages than its capacity in burst
> 86:     for (size_t i = 0; i < (sz / str_size); ++i) {
> 87:       lm.debug("a lot of log...");

Shouldn't this be passing `str`?

test/hotspot/gtest/logging/test_asynclog.cpp line 92:

> 90:     lm.debug("a lot of log...");
> 91:     lm.debug("a lot of log...");
> 92:     lm.debug("a lot of log...");

Shouldn't these be passing `str`?

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PR Review: https://git.openjdk.org/jdk/pull/24411#pullrequestreview-2745284593
PR Review Comment: https://git.openjdk.org/jdk/pull/24411#discussion_r2030279918
PR Review Comment: https://git.openjdk.org/jdk/pull/24411#discussion_r2030280254
PR Review Comment: https://git.openjdk.org/jdk/pull/24411#discussion_r2030280308