Forget to send to @core-lib-dev, the patch changed jdk code.
Thanks
Yumin
-------- Forwarded Message --------
Subject: RFR: 8247536: Support pre-generated MethodHandle lambda forms
in CDS
Date: Tue, 11 Aug 2020 07:44:34 -0700
From: Yumin Qi <yumin...@oracle.com>
To: hotspot-runtime-...@openjdk.java.net
Hi, Please reivew
bug: https://bugs.openjdk.java.net/browse/JDK-8247536
Webrev: http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-01/
Summary: CDS does not archive pre-generated lambda form classes for method
handles:
[0.142s][info][class,load] java.lang.invoke.LambdaForm$MH/0x0000000800066c40
source: __JVM_LookupDefineClass__
The method handle resolution if not found in the holder class, a class with the
method will be generated and loaded as vm internal created class and not
archived like above. Those class names are mangled as combination of the class
name and the class instance address.
In this patch, collect those method holder class names and their associated methods' signatures when user specify DumpLoadedClassList, and record them in the log file in a format similar to the output format from traced by -Djava.lang.invoke.MethodHandle.TRACE_RESOLVE=true, but here use another name for CDS: -Djava.lang.invoke.MethodHandle.CDS_TRACE_RESOLVE=true instead. The line prefix also changed from "[LF_RESOLVE]" to "@lambda-invoke-handle". At dump time, regenerate the holder class with those methods and replace the existing holder class and archived it. At runtime, the resolution of the holder class which contains those methods are loaded from CDS archive so avoid regenerating them again. The patch reorganized the code for Jlink plugin, so the new added InvokerBytecodeGeneratorHelper can be shared both by JLink plugin and CDS code. Also change made to the mangled generated class name at static dump, the class name combining the class name and a sequentially ordered
number instead of the class instance address, which looks like a random.
To use this feature, one can do the dump/run just like done for a static
dump/run, so no extra steps required.
1) java -XX:DumpLoadedClassList=myclasslist JavaApp
DumpLoadedClassList will turn on
-Djava.lang.invoke.MethodHandle.CDS_TRACE_RESOLVE=true
2) java -Xshare:dump -XX:SharedClassListFile=myclasslist
-XX:SharedArchiveFile=my.jsa JavaApp
3) java -Xshare:on -XX:SharedArchiveFile=my.jsa JavaApp
The performance on javac HelloWorld.java (javac-benchmark), no patch vs patch:
1: 2689285002 2641821474 (-47463528) ---- 391.720 382.990 (
-8.730) ----
2: 2687495085 2632969688 (-54525397) ---- 391.030 381.480 (
-9.550) -----
3: 2694664066 2636523114 (-58140952) ----- 390.610 382.550 (
-8.060) ----
4: 2686554164 2639355233 (-47198931) ---- 390.700 383.390 (
-7.310) ---
5: 2691072338 2633016687 (-58055651) ----- 388.990 382.360 (
-6.630) ---
6: 2684448174 2644191854 (-40256320) --- 389.450 382.990 (
-6.460) ---
7: 2694921227 2630505090 (-64416137) ----- 389.300 383.160 (
-6.140) ---
8: 2685209712 2639334320 (-45875392) ---- 388.370 381.060 (
-7.310) ---
9: 2695885942 2640618655 (-55267287) ---- 389.560 381.100 (
-8.460) ----
10: 2689162942 2635658943 (-53503999) ---- 389.690 379.110
(-10.580) -----
============================================================
2689866989 2637396210 (-52470778) ---- 389.941 382.017 (
-7.924) ----
instr delta = -52470778 -1.9507%
time delta = -7.924 ms -2.0321%
It will show much more improvement if compare with the default archive:
no patch patch
instr 3,996,847,605 3,320,928,995
time(s). 0.686835162 0.474933546
Tests:
1)jtreg on jdk/tools and hotspot/runtime local.
2) mach5 ter1,2
Thanks
Yumin
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