On 2020-06-08 19:31, Sergey Bylokhov wrote:
One of the reasons why -0s was used from the beginning is the
performance of the client related libraries, especially java2d.
Does anybody run or plan to run performance tests to check that we do
not have performance there?
As Claes say in the bug report, hopefully any potential performance
regression will show up in the general performance testing.
The idea here is, after all, that we will *increase* performance. :-)
Is there some specific library/behavior/test that you are worried about
that should show performance regression when we increase the
optimization level?
/Magnus
On 6/8/20 8:55 am, Magnus Ihse Bursie wrote:
From Jim's bug report:
"Mac OS X should use -O3 optimization level to be consistent with
other platforms and benefit Mac OS X java with the same performance
levels as other platforms.
Mac OS X has used -Os level optimization since management of the
platform JDK was handed over from Apple. This level of optimization
was Apple's policy, not OpenJDK's. The policy was established in a
time when memory was tight (I was there at the time.) Since then
other platforms have moved on, making the decision to target speed
over disk space. Specifically, using -O3 level optimization.
I've personally seen 20-30% improvement in performance in C/C++
applications using -O3 over -Os. But, of course, the performance team
should verify the affect on the JDK.
A 11% real time improvement can be seen with a rough HelloWord
compile/run."
I discussed this with Claes, our performance guru, and he agreed that
it is low risk enough that we can push this for JDK 15.
Bug: https://bugs.openjdk.java.net/browse/JDK-8246751
WebRev:
http://cr.openjdk.java.net/~ihse/JDK-8246751-macos-optimize-O3/webrev.01
/Magnus
