#!/usr/bin/env bash
# KNELPerf CPU benchmark — the missing CPU leg of the perf loop (#826).
# Runs ON the target host (or locally). Zero-install friendly: uses openssl
# (always present) plus sysbench when available. Output = TSV tag/value.
#
# Design notes:
#   - openssl speed = single+multi core crypto throughput (stable, comparable)
#   - sysbench cpu (if installed) = integer event rate
#   - /proc-derived context: governor, PSI at capture time
set -u
DUR=${KNELPERF_CPUBENCH_SECS:-10}

echo -e "metric\tvalue\tunit"

gov=$(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor 2>/dev/null || echo none)
echo -e "governor\t$gov\t-"
nproc=$(nproc)
echo -e "nproc\t$nproc\t-"

# openssl: 1 thread then all threads, aes-256-cbc (avx-sensitive) and sha256.
# Parse: LAST line whose first field is the algo; value = last numeric field
# (per-thread rows precede the aggregate row in -multi output).
for algo in aes-256-cbc sha256; do
  v=$(openssl speed -seconds "$DUR" "$algo" 2>/dev/null \
    | awk -v a="$algo" '$1==a{v=$NF} END{print v}')
  [ -n "${v:-}" ] && echo -e "openssl_${algo}_1t\t$v\tk/s"
  # -multi: per-thread rows precede the aggregate; keep the LAST match
  v=$(openssl speed -multi "$nproc" -seconds "$DUR" "$algo" 2>/dev/null \
    | awk -v a="$algo" '$1==a{v=$NF} END{print v}')
  [ -n "${v:-}" ] && echo -e "openssl_${algo}_${nproc}t\t$v\tk/s"
done

# sysbench (optional, if installed)
if command -v sysbench >/dev/null 2>&1; then
  ev=$(sysbench cpu --time=$((DUR*1000)) --threads=1 run 2>/dev/null \
    | awk -F'/s|events per second:/{for(i=1;i<=NF;i++) if($i ~ /^[0-9.]+$/){print $i; exit}}')
  [ -n "${ev:-}" ] && echo -e "sysbench_cpu_1t\t$ev\tevents/s"
  ev=$(sysbench cpu --time=$((DUR*1000)) --threads="$nproc" run 2>/dev/null \
    | awk -F'/s|events per second:/{for(i=1;i<=NF;i++) if($i ~ /^[0-9.]+$/){print $i; exit}}')
  [ -n "${ev:-}" ] && echo -e "sysbench_cpu_${nproc}t\t$ev\tevents/s"
else
  echo -e "sysbench_cpu\tabsent\t-"
fi

# PSI snapshot at capture time (context for the numbers above)
for res in cpu memory io; do
  v=$(awk '$1=="some"{for(i=2;i<=NF;i++) if($i ~ /^avg60=/){sub("avg60=","",$i); print $i; exit}}' \
    "/proc/pressure/$res" 2>/dev/null || echo 0)
  echo -e "psi_${res}_avg60\t$v\t%"
done
exit 0