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Hi all,<br>
<br>
Please, review this patch to
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move the code to determine the number of used workers out of
CollectionSetChooser::prepare_for_par_region_addition and up to
G1CollectorPolicy::record_concurrent_mark_cleanup_end, where the
worker threads are started. <br>
<br>
<a class="moz-txt-link-freetext"
href="http://cr.openjdk.java.net/%7Estefank/8080837">http://cr.openjdk.java.net/~stefank/8080837</a><br>
<a class="moz-txt-link-freetext"
href="https://bugs.openjdk.java.net/browse/JDK-8080837">https://bugs.openjdk.java.net/browse/JDK-8080837</a><br>
<br>
The patch also remove the redundant calculation of n_threads:<br>
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<pre><span class="removed">- uint n_threads = (uint) ParallelGCThreads;</span>
<span class="removed">- if (UseDynamicNumberOfGCThreads) {</span>
<span class="removed">- assert(G1CollectedHeap::heap()->workers()->active_workers() > 0,</span>
<span class="removed">- "Should have been set earlier");</span>
<span class="removed">- // This is defensive code. As the assertion above says, the number</span>
<span class="removed">- // of active threads should be > 0, but in case there is some path</span>
<span class="removed">- // or some improperly initialized variable with leads to no</span>
<span class="removed">- // active threads, protect against that in a product build.</span>
<span class="removed">- n_threads = MAX2(G1CollectedHeap::heap()->workers()->active_workers(),</span>
<span class="removed">- 1U);</span>
<span class="removed">- }
</span></pre>
since that logic is already present in the setup code of G1's
FlexibleWorkGang:<br>
_workers = new FlexibleWorkGang("GC Thread", ParallelGCThreads,<br>
/* are_GC_task_threads */true,<br>
/* are_ConcurrentGC_threads */false);<br>
<br>
and FlexibleWorkGang::set_active_workers:<br>
void set_active_workers(uint v) {<br>
assert(v <= _total_workers,<br>
"Trying to set more workers active than there are");<br>
_active_workers = MIN2(v, _total_workers);<br>
assert(v != 0, "Trying to set active workers to 0");<br>
_active_workers = MAX2(1U, _active_workers);<br>
assert(UseDynamicNumberOfGCThreads || _active_workers ==
_total_workers,<br>
"Unless dynamic should use total workers");<br>
}<br>
<br>
which is called at the previous collection pause.<br>
<br>
Thanks,<br>
StefanK<br>
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