On Fri, 23 Jul 2021 18:03:31 GMT, Sergey Chernyshev 
<github.com+6394632+serc...@openjdk.org> wrote:

> Dear colleagues,
> 
> Please review the patch that replaces the lambdas with anonymous classes 
> which solves the startup time regression as shown below.
> 
> I attached the Bytestacks flamegraphs for both original (regression) and 
> fixed versions. The flamegraphs clearly show the lambdas were causing the 
> performance issue.
> 
> [bytestacks_flamegraphs.zip](https://github.com/openjdk/jdk/files/6870446/bytestacks_flamegraphs.zip)
> 
> Although the proposed JDK-8270321 patch fixes the startup time (it might 
> appear even better than it was before the regression was introduced, i.e. 
> before JDK-8266310) and generally fixes the footprint regression, it may 
> increase MaxRSS slightly compared to the version before JDK-8266310, which is 
> shown in the below graphs. (updated)
> 
> ![StartupTime2](https://user-images.githubusercontent.com/6394632/126898224-a05fda62-f723-4f2c-9af9-e02cbfe1c9c8.png)
> 
> ![MaxRSS](https://user-images.githubusercontent.com/6394632/126822404-899ab904-efc1-4377-9e0d-d8cdb5c0e5d0.png)
> 
> (update: added ZGC graphs)
> 
> ![StartupTime_ZGC](https://user-images.githubusercontent.com/6394632/126898242-52c09582-c2a4-4623-aad2-f47055277193.png)
> 
> ![MaxRSS_ZGC](https://user-images.githubusercontent.com/6394632/126898244-31c3eeb5-a768-4a52-8960-960cc4a72d7b.png)
> 
> I additionally include the heap objects histograms to show the change does 
> not increase the total live objects size significantly with only 1000 bytes 
> the total difference, namely 1116128 bytes in 25002 live objects after the 
> proposed fix JDK-8270321 compared to 1115128 bytes in 24990 objects in the 
> version with the original patch reverted (i.e. before JDK-8266310).
> 
> [histograms.zip](https://github.com/openjdk/jdk/files/6870457/histograms.zip)
> 
> The patch was tested w/hotspot/tier1/tier2 test groups.

Marked as reviewed by mchung (Reviewer).

-------------

PR: https://git.openjdk.java.net/jdk/pull/4893

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