On Wed, 6 Sep 2023 07:02:53 GMT, Alan Bateman <al...@openjdk.org> wrote:
> `HotSpotDiagnosticMXBean.dumpThreads` and `jcmd Thread.dump_to_file` are slow > when there is a large number of threads. > > The thread dump can be sped up significantly with some small changes: > - Using println rather than format when printing the thread info and thread > stacks > - Wrap the underlying file output stream in a BufferedOutputStream > > With 200k virtual threads on macOS, the plain format thread dump goes from > 22s to 1.8s, and the json format thread dump goes from 31s to 2.8s on one > system that I tried. On a Linux system, also with 200k threads, the plain > thread dump goes from 8.7s to 2.9s, and the json format thread dump from > 12.4s to 4.5s. This looks good to me. ------------- Marked as reviewed by jpai (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/15581#pullrequestreview-1616563085
