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<p>I suspect that you are attempting to address something different
to what Alan had in mind here. I interpret Alan's response to be
about performance of the grouping, unrelated to whether
ephemerality is a thing or not.</p>
<p>(The inherent problems linked to ephemerality is discussed at
length in this thread)</p>
<div class="moz-cite-prefix">On 2026-02-06 09:40, Michal Domagala
wrote:<br>
</div>
<blockquote type="cite" cite="mid:CA+heAJDiyFYD_V8Py-XJ9F-aTAopKicnWLrkx1LKAH+67NSnvg@mail.gmail.com">
<div dir="ltr">I would share my reflections
<div>1. All "system" VT, "system" means f.e.created by
Structured Concurrency, automatically ends and never become
unreachable</div>
<div>2. Only application VT can become unreachable, f.e. when a
blocking queue became unreachable</div>
<div>3. Every VT is naturally GC-able, because only diagnostic
flag trackAllThreads saves unreached VT from release</div>
<div>4. Diagnostic is important</div>
<div>5. If trackAllThreads use weak reference, it can impact GC,
as potentially there can be millions of VT</div>
<div><br>
</div>
<div>Maybe it is worth to consider `Thread.ofEphemeral()`
tracked by weak reference<br>
1. Implementation effort is minimal, there will be two maps of
VT instead of one<br>
2. Performance effort is zero, because only intentional,
application VT can increase GC time (Volenti non fit iniuria)<br>
3. Diagnostic still works<br>
<br>
Regards <br>
Michal Domagala</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">pon., 12 sty 2026 o 13:41 Alan
Bateman <<a href="mailto:alan.bateman@oracle.com" target="_blank" moz-do-not-send="true" class="moz-txt-link-freetext">alan.bateman@oracle.com</a>>
napisał(a):<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
<br>
On 10/01/2026 15:55, Alex Miller wrote:<br>
> What is the likely future of the trackAllThreads flag?<br>
TBD. It's clearly an attractive nuisance right now and setting
it to <br>
false is specific to the root "thread grouping". There is some
<br>
performance work required in that area but otherwise I think
it needs to <br>
be removed.<br>
<br>
-Alan<br>
</blockquote>
</div>
</blockquote>
<pre class="moz-signature" cols="72">--
Cheers,
√
Viktor Klang
Software Architect, Java Platform Group
Oracle</pre>
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