<p dir="auto">The first build against master where this happened is <a href="https://ci.appveyor.com/project/StefanKarpinski/julia/build/1.0.5994/job/l01nwf0rwaedju0o" rel="nofollow">https://ci.appveyor.com/project/StefanKarpinski/julia/build/1.0.5994/job/l01nwf0rwaedju0o</a>, for <a class="commit-link" data-hovercard-type="commit" data-hovercard-url="https://github.com/JuliaLang/julia/commit/6ec7c21ff66bb5ec31e674134976d4c5beac7322/hovercard" href="https://github.com/JuliaLang/julia/commit/6ec7c21ff66bb5ec31e674134976d4c5beac7322"><tt>6ec7c21</tt></a></p>
<p dir="auto">I can reproduce locally, will try to see whether it's repeatable or intermittent (once I walk over to stata)</p>
<p dir="auto">I've gotten this to happen on 2 different Win64 computers, one Sandy Bridge, one Haswell. Happens when running <code class="notranslate">runtests.jl all</code> in parallel, seemingly more often the more cores I use for the tests. One of the workers gets stuck on its first test - so usually linalg, but I just got it to happen even on the strings test - while the rest of the workers happily finish everything else, waiting right before running <code class="notranslate">parallel</code> at the very end like they're supposed to.</p>
<p dir="auto">This isn't just the usual linalg slowness, I've left these going on multiple computers for half an hour or longer. The offending processes are stuck at 100% of a single core, but the memory consumption isn't changing at all.</p>
<p dir="auto">This doesn't happen on Win32, or when <code class="notranslate">JULIA_CPU_CORES=1</code>. Any ideas how to narrow this down? OpenBlas interaction? Win64 codegen problem? Something to do with libuv and task spawning? Ignore it and hope it doesn't show up in normal code?</p>