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Workforce: detach terminating threads instead of joining

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...which however brings the problem that we can no longer block the destructor
of WorkForce by simply joining on all joinable threads (there is a race
between testing joinable() and invoking join(), which does not tolerate
non-joinable state.

There is a second problem: we need to detect and clean-up terminated workers,
even for just finding out how many workers are still active. Fortunately
doing so also solves the waiting problem in the destructor
This commit is contained in:
Fischlurch 2023-09-08 04:26:29 +02:00
parent 81cab9a675
commit 5e16ed11bd
2 changed files with 63 additions and 6 deletions
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16
src/vault/gear/work-force.hpp
View file

@ -105,6 +105,7 @@ namespace gear {
}
ERROR_LOG_AND_IGNORE (threadpool, "defunct worker thread")
////////////////////////////////////////////////////////////////////////////OOO very important to have a reliable exit-hook here!!!
thread::detach();
}
activity::Proc
@ -166,10 +167,17 @@ namespace gear {
{
for (auto& w : workers_)
w.emergency.store(true, std::memory_order_relaxed);
for (auto& w : workers_)
if (w.joinable())
w.join();
workers_.clear();
using namespace std::chrono_literals; ///////////////////////7///WIP
do
std::this_thread::sleep_for(10ms);
while (0 < size());
}
size_t
size()
{
workers_.remove_if([](auto& w){ return not w.joinable(); });
return workers_.size();
}
private:

53
wiki/thinkPad.ichthyo.mm
View file

@ -79940,8 +79940,9 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1694016598589" ID="ID_1104497834" MODIFIED="1694016784846" TEXT="schrittweises Erh&#xf6;hen der Kapazit&#xe4;t">
<icon BUILTIN="flag-yellow"/>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1694016719052" ID="ID_841238568" MODIFIED="1694016784846" TEXT="Feststellen der aktuellen Auslastung">
<icon BUILTIN="flag-yellow"/>
<node COLOR="#338800" CREATED="1694016719052" ID="ID_841238568" MODIFIED="1694139706516" TEXT="Feststellen der aktuellen Auslastung">
<arrowlink COLOR="#89c79b" DESTINATION="ID_227859054" ENDARROW="Default" ENDINCLINATION="-428;33;" ID="Arrow_ID_103000260" STARTARROW="None" STARTINCLINATION="296;21;"/>
<icon BUILTIN="button_ok"/>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1694016740568" ID="ID_574870562" MODIFIED="1694016784847" TEXT="Speicher bereits terminierter Worker bereinigen">
<icon BUILTIN="flag-yellow"/>
@ -79955,6 +79956,54 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
<node CREATED="1694133131004" ID="ID_1711800389" MODIFIED="1694133165892" TEXT="sonst bleibt jedwede Exception-Behandlung h&#xe4;ngen">
<icon BUILTIN="messagebox_warning"/>
</node>
<node BACKGROUND_COLOR="#fdfdcf" COLOR="#ff0000" CREATED="1694138097733" ID="ID_198925376" MODIFIED="1694138118757" TEXT="Widerspruch zum Thread-Ende per detach()">
<icon BUILTIN="broken-line"/>
<node CREATED="1694138204919" ID="ID_353705069" MODIFIED="1694138245909" TEXT="nicht beehbarer Race: joinable() &#x21af; join()">
<node CREATED="1694138280757" ID="ID_1470165686" MODIFIED="1694138463589" TEXT="Symptom: sehe zuf&#xe4;llig eine invalid-Exception">
<richcontent TYPE="NOTE"><html>
<head/>
<body>
<ul>
<li>
Exception wird gefangen im WorkForce-dtor
</li>
<li>
mit Debugger nicht reproduzierbar
</li>
</ul>
<p>
Vermutung: zwischen joinable() &#8801; true und dem join()-Aufruf hat sich der Thread selber detached()
</p>
</body>
</html></richcontent>
</node>
<node CREATED="1694138465164" ID="ID_1130846770" MODIFIED="1694138532410" TEXT="grunds&#xe4;tzlich aber auch ein konzeptioneller Widerspruch">
<richcontent TYPE="NOTE"><html>
<head/>
<body>
<p>
entweder ein Thread soll gereaped werden, oder ein Thread verschwindet einfach von der Bildfl&#228;che
</p>
</body>
</html></richcontent>
</node>
</node>
<node COLOR="#5b280f" CREATED="1694138534943" ID="ID_1131160592" MODIFIED="1694139586481" TEXT="L&#xf6;sung per join()">
<icon BUILTIN="button_cancel"/>
<node CREATED="1694138546802" ID="ID_1142646153" MODIFIED="1694138564394" TEXT="Problem: beendete Threads nicht erkennbar"/>
<node CREATED="1694138567806" ID="ID_1862534308" MODIFIED="1694138595694" TEXT="&#x27f9; nicht klar wie viele Threads noch aktiv sind"/>
<node CREATED="1694138600978" ID="ID_1698300974" MODIFIED="1694138638937" TEXT="&#x27f9; m&#xfc;&#xdf;te dann selber eine &#xbb;aktiv&#xab;-Flag einf&#xfc;hren"/>
</node>
<node CREATED="1694138649464" ID="ID_21789098" MODIFIED="1694139584363" TEXT="L&#xf6;sung per detach()">
<icon BUILTIN="forward"/>
<node CREATED="1694138670160" ID="ID_328887585" MODIFIED="1694138689001" TEXT="Problem: mu&#xdf; am Ende doch irgendwie auf die Threads warten"/>
<node CREATED="1694138769195" ID="ID_508739227" MODIFIED="1694138812818" TEXT="&#x27f9; m&#xfc;&#xdf;te dann aktiv auf joinable() &#x2261; false warten"/>
<node COLOR="#338800" CREATED="1694139634650" ID="ID_227859054" MODIFIED="1694139693900" TEXT="L&#xf6;sung: sleep-wait auf size() &#x2261; 0">
<linktarget COLOR="#89c79b" DESTINATION="ID_227859054" ENDARROW="Default" ENDINCLINATION="-428;33;" ID="Arrow_ID_103000260" SOURCE="ID_841238568" STARTARROW="None" STARTINCLINATION="296;21;"/>
<icon BUILTIN="button_ok"/>
</node>
</node>
</node>
</node>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1693841488183" HGAP="-2" ID="ID_671611566" MODIFIED="1693841514321" TEXT="WorkForce_test (Komponententest)" VSHIFT="-3">