(S) 8237750: Load libzip.so only if necessary

[Dean Long]

Does UseAOT really need libzip?

dl

On 5/1/20 10:24 AM, Yumin Qi wrote:
> Hi, please review:
> bug 8237750: https://bugs.openjdk.java.net/browse/JDK-8237750
> webrev: http://cr.openjdk.java.net/~minqi/8237750/webrev-01/
> Summary:
>   zip library is loaded unconditionally at start up but it is only 
> needed when
>   1) bootclasspath contains zip or
>   2) UseAOT enabled or
>   3) VerifySharedArchive turned on or
>   4) CDS archives custom loaded classes
>    If none of above in java application, it is not necessary to have 
> zip library loaded.
>
>   Solution by loading zip library on demand when needed.
>
> Performance for java -Xint version:
>
> Results of " perf stat -r 50 bin/java -Xshare:on 
> -XX:SharedArchiveFile=jdk2.jsa -Xint -version "
>    1:     59611556    59450206 (-161350)      -----     39.799 40.274 
> (  0.475)    ++
>    2:     59602708    59425234 (-177474)      -----     40.591 41.183 
> (  0.592)    ++
>    3:     59579718    59441272 (-138446)      ----      40.777 40.471 
> ( -0.306)      -
>    4:     59584882    59410155 (-174727)      -----     40.824 40.233 
> ( -0.591)      --
>    5:     59590998    59447252 (-143746)      ----      40.400 40.493 
> (  0.093)
>    6:     59589523    59441934 (-147589)      ----      40.475 40.064 
> ( -0.411)      --
>    7:     59581820    59413612 (-168208)      -----     39.763 40.077 
> (  0.314)     +
>    8:     59593678    59418738 (-174940)      -----     40.912 39.724 
> ( -1.188)      -----
>    9:     59573058    59412554 (-160504)      -----     40.126 40.033 
> ( -0.093)
>   10:     59591469    59419291 (-172178)      -----     40.731 40.689 
> ( -0.042)
> ============================================================
>           59589940    59428022 (-161917)      -----     40.438 40.322 
> ( -0.116)
> instr delta =      -161917    -0.2717%
> time  delta =       -0.116 ms -0.2859%
>
> Tests: hs-tier1-4.
> Due to zip library not loaded at default, I removed 'zip' from pmap 
> list in test case: *test/hotspot/jtreg/serviceability/sa/ClhsdbPmap.java
>
> **
> * Thanks
> Yumin