On Tue, 21 Mar 2023 22:38:18 GMT, Chris Plummer <cjplum...@openjdk.org> wrote:
>> There are two GC related issues with this test that are being addressed. The >> test was limiting the heap size to 6m so if there is still a leak, it will >> be detected quickly. This proved to be too small of a size when using ZGC. >> For the most part changing the size to 7m fixed this issue. However, I was >> still seeing frequent issues with ZGC on macOS. This is explained by >> [JDK-8304449](https://bugs.openjdk.org/browse/JDK-8304449), which noticed >> (rarely) OOME on macos even when not using ZGC. From JDK-8304449: >> >> "macOS has a thread behavior that is not seen on linux and windows that is >> causing more memory usage, which sometimes leads to this unexpected OOME. >> The debuggee side of the test constantly creates threads that do little more >> than a short sleep. It has a counter of "live" threads, and won't let that >> go over 500. On the debugger side it is just tracking ThreadStartEvents and >> ThreadDeathEvents. It keep tracks of threads (ThreadReferences) for which a >> ThreadStartEvent had been received but a ThreadDeathEvent has not. On linux >> and windows the count of outstanding threads is generally in the 200-400 >> range, sometimes briefly going over 500. However, on macOS it is closer to >> 2400. This means a lot more ThreadReferences being tracked, which means more >> memory usage, so sometimes you see an OOME on macOS as a result. " >> >> The `threads` collection mainly existed just so its size could be used to >> log the number of outstanding ThreadDeathEvents. I got rid of the `threads` >> collection and instead am just tracking the number of ThreadStartEvents and >> ThreadDeathEvents, and computing the difference to get the number of >> outstanding ThreadDeathEvents. > > Chris Plummer has updated the pull request incrementally with one additional > commit since the last revision: > > get rid of some locals that are not needed Just the one test. ------------- PR Comment: https://git.openjdk.org/jdk/pull/13130#issuecomment-1489294898
