> 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 ------------- Changes: - all: https://git.openjdk.org/jdk/pull/13130/files - new: https://git.openjdk.org/jdk/pull/13130/files/2a2efb13..89f73875 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=13130&range=01 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13130&range=00-01 Stats: 3 lines in 1 file changed: 0 ins; 3 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/13130.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/13130/head:pull/13130 PR: https://git.openjdk.org/jdk/pull/13130
