RFR: 8360783: CTW: Skip deoptimization between tiers [v2]

[Aleksey Shipilev]

> When profiling CTW runs, I noticed we spend a lot of time dealing with deoptimization. We do this excessively, deoptimizing before compilation on every tier. This is excessive: Hotspot honors compilation requests on subsequent levels without the need for explicit deoptimization. Not doing deopt between tiers greatly improves CTW performance. 
> 
> A taste of improvements, about 15% less CPU spent:
> 
> 
> $ time make test TEST=applications/ctw/modules
> 
> # Current
> real	5m1.616s
> user	79m41.398s
> sys	14m39.607s
> 
> # Patched
> real	3m55.411s
> user	69m19.227s
> sys	5m24.323s
> 
> 
> The compilation still works as expected, progressing through tiers 1..4:
> 
> 
> $ JAVA_OPTIONS="-XX:+PrintCompilation -XX:CICompilerCount=2" ./ctw.sh modules:jdk.compiler | tee out
> ...
> $ grep sun.tools.serialver.resources.serialver_de::getContents out
> 101783 55033    b  1       sun.tools.serialver.resources.serialver_de::getContents (108 bytes)
> 101785 55036    b  2       sun.tools.serialver.resources.serialver_de::getContents (108 bytes)
> 101786 55033       1       sun.tools.serialver.resources.serialver_de::getContents (108 bytes)   made not entrant: not used
> 101786 55038    b  3       sun.tools.serialver.resources.serialver_de::getContents (108 bytes)
> 101787 55036       2       sun.tools.serialver.resources.serialver_de::getContents (108 bytes)   made not entrant: not used
> 101792 55040    b  4       sun.tools.serialver.resources.serialver_de::getContents (108 bytes)
> 101797 55038       3       sun.tools.serialver.resources.serialver_de::getContents (108 bytes)   made not entrant: not used
> 101798 55040       4       sun.tools.serialver.resources.serialver_de::getContents (108 bytes)   made not entrant: marked for deoptimization

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Update test/hotspot/jtreg/testlibrary/ctw/src/sun/hotspot/tools/ctw/Compiler.java
  
  Co-authored-by: Tobias Hartmann <tobias.hartmann at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26013/files
  - new: https://git.openjdk.org/jdk/pull/26013/files/7dce90f7..34913a48

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26013&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26013&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26013.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26013/head:pull/26013

PR: https://git.openjdk.org/jdk/pull/26013