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<div class="moz-cite-prefix">Hi Mikael,<br>
<br>
On 4/21/16 4:02 AM, Mikael Gerdin wrote:<br>
</div>
<blockquote cite="mid:57188901.9020007@oracle.com" type="cite">Hi
Derek,
<br>
<br>
On 2016-04-20 23:48, Derek White wrote:
<br>
<blockquote type="cite">Still looking for reviews for a small fix
for a P2 bug...
<br>
<br>
Thanks!
<br>
<br>
On 4/7/16 6:07 PM, Derek White wrote:
<br>
<blockquote type="cite">Summary:
<br>
The remaining part of this bug deals with running out of
address space
<br>
on 32-bit JVMs running on Win64. This fix is simply to have a
hard
<br>
limit on GC threads (still larger than necessary) on 32-bit
JVMs. The
<br>
new limit is 16 (2 * switch_pt).
<br>
<br>
Note that this overlaps somewhat with several "# of GC thread"
bugs
<br>
including:
<br>
- 8131932
<a class="moz-txt-link-rfc2396E" href="https://bugs.openjdk.java.net/browse/JDK-8131932"><https://bugs.openjdk.java.net/browse/JDK-8131932></a> :
<br>
Ergonomics oversize number of GC threads for small JVMs on
large systems
<br>
- 8153225
<a class="moz-txt-link-rfc2396E" href="https://bugs.openjdk.java.net/browse/JDK-8153225"><https://bugs.openjdk.java.net/browse/JDK-8153225></a>: G1
<br>
creates too many concurrent refinement threads by default
<br>
- 7189147
<a class="moz-txt-link-rfc2396E" href="https://bugs.openjdk.java.net/browse/JDK-7189147"><https://bugs.openjdk.java.net/browse/JDK-7189147></a>: GC
<br>
threads should be created as needed not all at once
<br>
<br>
Doing the correct thing in general will require a lot more
performance
<br>
analysis. The fix here is simple, only affects 32-bit JVMs
running on
<br>
>= 24 core machines, and will reduce OOM crashes in nightly
testing.
<br>
<br>
BUG: 8134889
<a class="moz-txt-link-rfc2396E" href="https://bugs.openjdk.java.net/browse/JDK-8134889"><https://bugs.openjdk.java.net/browse/JDK-8134889></a>
<br>
WEBREV: <a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~drwhite/8134889/webrev.01/">http://cr.openjdk.java.net/~drwhite/8134889/webrev.01/</a>
<br>
</blockquote>
</blockquote>
<br>
Fix looks good.
<br>
I wonder about the cast to unsigned int, though.
<br>
It seems weird that it's needed since all the other operands are
unsigned ints in the calculation.
<br>
</blockquote>
<br>
Yes, that does look weird. I can't recall why I added it either.<br>
<blockquote><tt> unsigned int switch_pt = bar;</tt><tt><br>
</tt><tt> unsigned int threads = foo;</tt><tt><br>
</tt><tt> threads = MIN2(threads, 2*switch_pt)</tt><br>
</blockquote>
Wait a minute, according to the interweb, the type of the literal
'2' is "int" (eg. signed). I think one compiler complained on a jprt
run. Doing a jprt run without the cast...<br>
<br>
Thanks!<br>
<br>
- Derek<br>
<blockquote cite="mid:57188901.9020007@oracle.com" type="cite">
<br>
/Mikael
<br>
<br>
<blockquote type="cite">
<blockquote type="cite">TESTS: jprt
<br>
<br>
</blockquote>
<br>
</blockquote>
</blockquote>
<br>
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