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<div class="moz-cite-prefix">On 11/22/2013 4:33 AM, Bengt Rutisson
wrote:<br>
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<div> Do we need the flag AdjustGCThreadsToCores? It
seems like this is a good change and it is always
nice to reduce the number of flags we have. If you
feel unsure about the change it may be good to be
able to disable it, but in general I think it would
be better to decide that this is the default
behavior and go with it.<br>
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<div>I have no strong opinion. If you guys can confirm the
improvements and feel like you don't need the flag, that
would be ideal.</div>
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Yes, this is an interesting dilemma. Personally I don't think I
have the cycles right now to do any performance testing of this
fix. But I assume that you don't have access to enough machines
and benchmarks to test this properly on all supported platforms.
I'll bring this up internally to see if there is any process for
handling this type of situation...<br>
<br>
Since your change is for Linux only and you have done the
measurements there, I'm fine with your results. I would prefer
skipping the AdjustGCThreadsToCores flag based on the data you
provided. Especially since we can still set ParallelGCThreads
explicitly on the command line if we need to work around a
regression somewhere.<br>
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I fully expect to need the AdjustGCThreadsToCores flag on Sparc so I
would prefer<br>
it be left in. Make it an experimental flag to make it easier to
remove later<br>
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<pre><span class="new">1405 <font color="#ff0000">experimental</font>(bool, AdjustGCThreadsToCores, true, \</span>
<span class="new">1406 "Create GC worker threads with respect to the number of physical "\</span>
<span class="new">1407 "cores available from the CPU mask. Ignores hardware threads") \</span>
<span class="new">1408 </span></pre>
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We do have the ParallelGCThreads flag to workaround regressions but
users don't<br>
know what value is currently set by the ergonomics so won't know
what value<br>
to use for ParallelGCThreads to workaround a regression. <br>
<br>
Jon<br>
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