Looks good.
/Erik
On 2020-06-22 03:39, Vladimir Kempik wrote:
Hello
Thanks for looking into this Magnus.
Here is updated version of webrev -
http://cr.openjdk.java.net/~vkempik/8243470/webrev.01/
<http://cr.openjdk.java.net/~vkempik/8243470/webrev.01/>
effectively it does exactly the same as previous version, I have removed the
version check for clang.
Thanks, Vladimir
4 июня 2020 г., в 16:04, Magnus Ihse Bursie <magnus.ihse.bur...@oracle.com>
написал(а):
On 2020-06-03 20:07, Magnus Ihse Bursie wrote:
Thanks for cc:ing us.
This is not the correct way to check for compiler versions. Nor is it the
correct place.
I don't have time for a full reply tonight, but will return with a better reply
tomorrow.
Ok, I have now looked more into this.
You are apparently want to check for Xcode version, not clang version. This is
not the same. Note that clang can be used on Linux as well. Apple is basically
dropping the normal clang versioning and replacing it with their own, messed-up
version which somewhat resembles the corresponding Xcode version, but is not
identical. Horray. :-/ (For those interested, have a look at
https://gist.github.com/yamaya/2924292.)
Anyway. We do not support Xcode prior to 8. You seem to have tested from 8 and
up, so this patch should be applied unconditionally. That is, just remove the
-O1 special thing.
/Magnus
/Magnus
On 2020-06-03 19:47, Daniel D. Daugherty wrote:
Adding build-dev@... since this is a build system change.
As for the right HotSpot team, I'm not sure who should be making
the call on changing the way unsafe.cpp is built for macOSX. My guess
when I moved the bug to hotspot/runtime was that someone on the Runtime
team would know, but...
Dan
On 6/3/20 1:38 PM, Vladimir Kempik wrote:
Hello
Can somebody please review this simple change ?
Thanks
6 мая 2020 г., в 12:43, Vladimir Kempik <vkem...@azul.com> написал(а):
Adding hotspot-runtime-dev
23 апр. 2020 г., в 18:26, Vladimir Kempik <vkem...@azul.com> написал(а):
Hello
Please review a fix for JDK-8243470
Long time ago as part of JEP284: New HotSpot Build System this fix was applied
to jdk9 https://bugs.openjdk.java.net/browse/JDK-8152666
At that time it was decided to lower optimisation level for unsafe.cpp from O2
to O1 only for clang on Macosx.
I suppose it was done due to issues in Set/Get<Object> helper functions where
too optimistic optimisations were eliminating some null pointer checks. it was
probably a clang bug.
That issue could be checked with test jdk/test/sun/misc/CopyMemory.java.
I believe that workaround (going from O2 to O1) produced this issue -
https://bugs.openjdk.java.net/browse/JDK-8234963 (Thread.getStackTrace is slow
with clang).
JDK-8234963 can only be seen on mac with libjvm compiled by clang.
Here I propose the patch which eliminates that workaround for clang 8+.
I have tested clang versions 8/9/9.1/10, all of them showed good results:
1) CopyMemory test passes fine on 11/14/15.
2) jdk11/jdk14 passed tck. Regression testing were good as well. jdk15: no new
failures in tck.
3) The testRandom "benchmark" from 8234963 shows great improvements on my
machine, going down from ~200 seconds to ~150 seconds (the newer clang the better
result). For comparision, gcc built libjvm for jdk11 shows ~130 seconds on my machine.
The webrev: http://cr.openjdk.java.net/~vkempik/8243470/webrev.00/
getStackTrace benchmark:
http://cr.openjdk.java.net/~vkempik/8243470/TestRandom.java
The bug: https://bugs.openjdk.java.net/browse/JDK-8243470
Thanks, Vladimir
