#!/bin/bash
# Zstd perf.data compression/decompression

# SPDX-License-Identifier: GPL-2.0

trace_file=$(mktemp /tmp/perf.data.XXX)
perf_tool=perf

skip_if_no_z_record() {
 $perf_tool record -h 2>&1 | grep -q '\-z, \-\-compression\-level'
}

collect_z_record() {
 echo "Collecting compressed record file:"
 [ "$(uname -m)" != s390x ] && gflag='-g'
 $perf_tool record -o "$trace_file" $gflag -z -F 5000 -- \
  dd count=500 if=/dev/urandom of=/dev/null
}

check_compressed_stats() {
 echo "Checking compressed events stats:"
 $perf_tool report -i "$trace_file" --header --stats | \
  grep -E "(# compressed : Zstd,)|(COMPRESSED events:)"
}

check_compressed_output() {
 $perf_tool inject -i "$trace_file" -o "$trace_file.decomp" &&
 $perf_tool report -i "$trace_file" --stdio -F comm,dso,sym | head -n -3 > "$trace_file.comp.output" &&
 $perf_tool report -i "$trace_file.decomp" --stdio -F comm,dso,sym | head -n -3 > "$trace_file.decomp.output" &&
 diff "$trace_file.comp.output" "$trace_file.decomp.output"
}

skip_if_no_z_record || exit 2
collect_z_record && check_compressed_stats && check_compressed_output
err=$?
rm -f "$trace_file*"
exit $err