#!/usr/bin/env bash
# What the JVM decides from the pod's resources, with no JVM flags at all.
# -> docs/output/jvm-ergonomics.txt
set -uo pipefail
source "$(dirname "$0")/env.sh"
# cpu.limit | cpu.request | mem.request | mem.limit. Requests are deliberately small and constant:
# the JVM ignores them (JDK-8281181 removed CPU shares from the calculation in JDK 19), and small
# requests let every case schedule on a 2-CPU node.
CASES=(
  "none|100m|256Mi|2Gi"
  "500m|100m|256Mi|512Mi"
  "1|100m|256Mi|1Gi"
  "1|100m|256Mi|2Gi"
  "1500m|100m|256Mi|2Gi"
  "2|100m|256Mi|1Gi"
  "2|100m|256Mi|1700Mi"
  "2|100m|256Mi|1800Mi"
  "2|100m|256Mi|4Gi"
)
flag() { grep -E "^ *[a-z_]+ +$1 " <<< "$2" | awk '{print $4}'; }
{
  echo "# JVM ergonomics per pod resources. Image: $IMAGE, no JVM options. Node: $(nproc) CPUs."
  echo "# cgroup v$( [ -f /sys/fs/cgroup/cgroup.controllers ] && echo 2 || echo 1 ) node; see docs/03-jvm-ergonomics.md for the v2 equivalents."
  echo
  printf '%-7s %-7s %-7s %-7s | %-5s %-10s %9s %6s %6s %6s\n' "cpu.req" "cpu.lim" "mem.req" "mem.lim" "CPUs" "GC" "MaxHeap" "PGCThr" "CGCThr" "JITThr"
  i=0
  for c in "${CASES[@]}"; do
    IFS='|' read -r cl cr mr ml <<< "$c"
    if [ "$cl" = none ]; then res="{requests: {cpu: $cr, memory: $mr}, limits: {memory: $ml}}"
    else res="{requests: {cpu: $cr, memory: $mr}, limits: {cpu: $cl, memory: $ml}}"; fi
    out=$(oneoff "erg-$i" "$res" java -XX:+PrintFlagsFinal -version 2>&1)
    gc=SerialGC; [ "$(flag UseG1GC "$out")" = true ] && gc=G1GC; [ "$(flag UseParallelGC "$out")" = true ] && gc=ParallelGC
    cpus=$(oneoff "erg-$i" "$res" java -XshowSettings:system -version 2>&1 | grep -i 'Effective CPU Count' | awk -F: '{gsub(/ /,"",$2); print $2}')
    heap=$(( $(flag MaxHeapSize "$out") / 1024 / 1024 ))
    printf '%-7s %-7s %-7s %-7s | %-5s %-10s %8sM %6s %6s %6s\n' "$cr" "$cl" "$mr" "$ml" "$cpus" "$gc" "$heap" \
      "$(flag ParallelGCThreads "$out")" "$(flag ConcGCThreads "$out")" "$(flag CICompilerCount "$out")"
    i=$((i+1))
  done
  echo
  echo "# java -XshowSettings:system for the 1500m case:"
  oneoff erg-show "{requests: {cpu: 100m, memory: 256Mi}, limits: {cpu: 1500m, memory: 2Gi}}" java -XshowSettings:system -version 2>&1 | grep -vE '^(openjdk|OpenJDK)' 
} | tee "$OUT/jvm-ergonomics.txt"