RFR 8165372 : StackWalker performance regression following JDK-8147039
coleen.phillimore at oracle.com
Mon Sep 19 19:46:01 UTC 2016
+ if (need_method_info(mode) == false && get_caller_class(mode) &&
+ if (!need_method_info(mode) && get_caller_class(mode) &&
And the two instances of this:
+ Handle stackFrame(frames_array->obj_at(index));
+ Handle stackFrame(THREAD, frames_array->obj_at(index));
Other than these minor comments, I think this looks really good.
On 9/19/16 3:35 PM, Brent Christian wrote:
> Please review my fix for 8165372 : "StackWalker performance regression
> following JDK-8147039"
> Bug: https://bugs.openjdk.java.net/browse/JDK-8165372
> Webrev: http://cr.openjdk.java.net/~bchristi/8165372/webrev.00/
> 8147039 reimplemented stack walking using javaVFrames in place of
> vframeStream, in order to give correct results for the experimental
> LiveStackFrame feature. However, this also resulted in a significant
> StackWalker performance regression (25-60%, depending on specific
> operation and stack depth).
> This fix includes stack walking implemented both ways, encapsulated
> within C++ classes. JavaFrameStream provides the speed we had before
> for most use cases, while LiveFrameStream provides correct results
> when using LiveStackFrames.
> Performance is much improved, back within 5% or so of pre-8147039
> levels, based on my measurements.
> 1. http://hg.openjdk.java.net/jdk9/hs/hotspot/rev/6174ad93770c
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