perf test: Add set of perf record LBR tests

Adds coverage for LBR operations and LBR callgraph.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anne Macedo <retpolanne@posteo.net>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240808054644.1286065-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/shell/record_lbr.sh

@@ -0,0 +1,161 @@
+#!/bin/bash
+# perf record LBR tests
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+if [ ! -f /sys/devices/cpu/caps/branches ]
+then
+  echo "Skip: only x86 CPUs support LBR"
+  exit 2
+fi
+
+err=0
+perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
+
+cleanup() {
+  rm -rf "${perfdata}"
+  rm -rf "${perfdata}".old
+  rm -rf "${perfdata}".txt
+
+  trap - EXIT TERM INT
+}
+
+trap_cleanup() {
+  cleanup
+  exit 1
+}
+trap trap_cleanup EXIT TERM INT
+
+
+lbr_callgraph_test() {
+  test="LBR callgraph"
+
+  echo "$test"
+  if ! perf record -e cycles --call-graph lbr -o "${perfdata}" perf test -w thloop
+  then
+    echo "$test [Failed support missing]"
+    if [ $err -eq 0 ]
+    then
+      err=2
+    fi
+    return
+  fi
+
+  if ! perf report --stitch-lbr -i "${perfdata}" > "${perfdata}".txt
+  then
+    cat "${perfdata}".txt
+    echo "$test [Failed in perf report]"
+    err=1
+    return
+  fi
+
+  echo "$test [Success]"
+}
+
+lbr_test() {
+  local branch_flags=$1
+  local test="LBR $2 test"
+  local threshold=$3
+  local out
+  local sam_nr
+  local bs_nr
+  local zero_nr
+  local r
+
+  echo "$test"
+  if ! perf record -e cycles $branch_flags -o "${perfdata}" perf test -w thloop
+  then
+    echo "$test [Failed support missing]"
+    perf record -e cycles $branch_flags -o "${perfdata}" perf test -w thloop || true
+    if [ $err -eq 0 ]
+    then
+      err=2
+    fi
+    return
+  fi
+
+  out=$(perf report -D -i "${perfdata}" 2> /dev/null | grep -A1 'PERF_RECORD_SAMPLE')
+  sam_nr=$(echo "$out" | grep -c 'PERF_RECORD_SAMPLE' || true)
+  if [ $sam_nr -eq 0 ]
+  then
+    echo "$test [Failed no samples captured]"
+    err=1
+    return
+  fi
+  echo "$test: $sam_nr samples"
+
+  bs_nr=$(echo "$out" | grep -c 'branch stack: nr:' || true)
+  if [ $sam_nr -ne $bs_nr ]
+  then
+    echo "$test [Failed samples missing branch stacks]"
+    err=1
+    return
+  fi
+
+  zero_nr=$(echo "$out" | grep -c 'branch stack: nr:0' || true)
+  r=$(($zero_nr * 100 / $bs_nr))
+  if [ $r -gt $threshold ]; then
+    echo "$test [Failed empty br stack ratio exceed $threshold%: $r%]"
+    err=1
+    return
+  fi
+
+  echo "$test [Success]"
+}
+
+parallel_lbr_test() {
+  err=0
+  perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
+  lbr_test "$1" "$2" "$3"
+  cleanup
+  exit $err
+}
+
+lbr_callgraph_test
+
+# Sequential
+lbr_test "-b" "any branch" 2
+lbr_test "-j any_call" "any call" 2
+lbr_test "-j any_ret" "any ret" 2
+lbr_test "-j ind_call" "any indirect call" 2
+lbr_test "-j ind_jmp" "any indirect jump" 100
+lbr_test "-j call" "direct calls" 2
+lbr_test "-j ind_call,u" "any indirect user call" 100
+lbr_test "-a -b" "system wide any branch" 2
+lbr_test "-a -j any_call" "system wide any call" 2
+
+# Parallel
+parallel_lbr_test "-b" "parallel any branch" 100 &
+pid1=$!
+parallel_lbr_test "-j any_call" "parallel any call" 100 &
+pid2=$!
+parallel_lbr_test "-j any_ret" "parallel any ret" 100 &
+pid3=$!
+parallel_lbr_test "-j ind_call" "parallel any indirect call" 100 &
+pid4=$!
+parallel_lbr_test "-j ind_jmp" "parallel any indirect jump" 100 &
+pid5=$!
+parallel_lbr_test "-j call" "parallel direct calls" 100 &
+pid6=$!
+parallel_lbr_test "-j ind_call,u" "parallel any indirect user call" 100 &
+pid7=$!
+parallel_lbr_test "-a -b" "parallel system wide any branch" 100 &
+pid8=$!
+parallel_lbr_test "-a -j any_call" "parallel system wide any call" 100 &
+pid9=$!
+
+for pid in $pid1 $pid2 $pid3 $pid4 $pid5 $pid6 $pid7 $pid8 $pid9
+do
+  set +e
+  wait $pid
+  child_err=$?
+  set -e
+  if ([ $err -eq 2 ] && [ $child_err -eq 1 ]) || [ $err -eq 0 ]
+  then
+    err=$child_err
+  fi
+done
+
+cleanup
+exit $err