[PATCH v1 1/8] perf test: Skip data_type_profiling when the PMU cannot record memory events

[Arnaldo Carvalho de Melo <acme@kernel.org>]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

The test records with 'perf mem record' in per-thread mode and its only
guard matches one specific message:

  perf mem record -o /dev/null -- true 2>&1 | \
        grep -q "failed: no PMU supports the memory events" && exit 2

A PMU that has memory events but refuses them per-thread falls through
it, and AMD IBS does:

  $ perf mem record -o /dev/null -- true
  Error:
  Failure to open event 'ibs_op/ldlat=0/u' on PMU 'ibs_op' which will be removed.
  Invalid event (ibs_op/ldlat=0/u) in per-thread mode, enable system wide with '-a'.
  Error:
  Failure to open any events for recording.

What follows is not a skip either.  The script runs under 'set -e', so
the bare 'perf mem record' in test_basic_annotate() aborts it through the
EXIT trap, which reports a signal that never happened and exits 1:

  Basic Rust perf annotate test
  Unexpected signal in test_basic_annotate

so 'perf test' turns "this PMU cannot record these events" into a test
failure:

  $ perf test "data type profiling"
   87: perf data type profiling tests             : FAILED!

The 'if [ "x$?" != "x0" ]' right below the record was meant to report
"[Failed: perf record]" and carry on with the other cases, but under
'set -e' it is dead code: the shell is gone before it is reached.  The
same goes for the 'perf annotate' call below it.

Skip when a trivial per-thread 'perf mem record' fails, and put both
commands in the condition of an 'if', where 'set -e' leaves them alone,
so that the
reporting works for the cases where only one workload cannot be recorded
or annotated:

  $ perf test "data type profiling"
   87: perf data type profiling tests             : Skip

and, with just the new skip guard disabled on the same box, every case
reports its failure instead of the first one aborting the run:

  Basic Rust perf annotate test
  Basic annotate [Failed: perf record]
  Pipe Rust perf annotate test
  Pipe annotate [Failed: perf record]
  Basic C perf annotate test
  Basic annotate [Failed: perf record]
  Pipe C perf annotate test
  Pipe annotate [Failed: perf record]

Assisted-by: LLM
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/tests/shell/data_type_profiling.sh | 46 +++++++++++++++----
 1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/tools/perf/tests/shell/data_type_profiling.sh b/tools/perf/tests/shell/data_type_profiling.sh
index eca694600a0478d2..a916c410274aa888 100755
--- a/tools/perf/tests/shell/data_type_profiling.sh
+++ b/tools/perf/tests/shell/data_type_profiling.sh
@@ -19,6 +19,15 @@ perfout=$(mktemp /tmp/__perf_test.perf.out.XXXXX)
 perf mem record -o /dev/null -- true  2>&1 | \
   		grep -q "failed: no PMU supports the memory events" && exit 2
 
+# Skip if per-thread mem record is not supported on this PMU (e.g. AMD IBS
+# needs system-wide '-a'): it is what the test records with below, and a
+# failing record must not be reported as a test failure.
+if ! perf mem record -o /dev/null -- true 2>/dev/null
+then
+  echo "Skip: cannot record memory events on this PMU"
+  exit 2
+fi
+
 cleanup() {
   rm -rf "${perfdata}" "${perfout}"
   rm -rf "${perfdata}".old
@@ -52,25 +61,42 @@ test_basic_annotate() {
     index=1 ;;
   esac
 
+  # Under 'set -e' a bare failing command aborts the script through the EXIT
+  # trap, so the commands that report a failure have to be the condition of
+  # an 'if' for that reporting to ever happen.
   if [ "x${mode}" == "xBasic" ]
   then
-    perf mem record -o "${perfdata}" ${testprogs[$index]} 2> /dev/null
+    if ! perf mem record -o "${perfdata}" ${testprogs[$index]} 2> /dev/null
+    then
+      echo "${mode} annotate [Failed: perf record]"
+      err=1
+      return
+    fi
   else
-    perf mem record -o - ${testprogs[$index]} 2> /dev/null > "${perfdata}"
-  fi
-  if [ "x$?" != "x0" ]
-  then
-    echo "${mode} annotate [Failed: perf record]"
-    err=1
-    return
+    if ! perf mem record -o - ${testprogs[$index]} 2> /dev/null > "${perfdata}"
+    then
+      echo "${mode} annotate [Failed: perf record]"
+      err=1
+      return
+    fi
   fi
 
   # Generate the annotated output file
   if [ "x${mode}" == "xBasic" ]
   then
-    perf annotate --code-with-type -i "${perfdata}" --stdio --percent-limit 1 2> /dev/null > "${perfout}"
+    if ! perf annotate --code-with-type -i "${perfdata}" --stdio --percent-limit 1 2> /dev/null > "${perfout}"
+    then
+      echo "${mode} annotate [Failed: perf annotate]"
+      err=1
+      return
+    fi
   else
-    perf annotate --code-with-type -i - --stdio 2> /dev/null --percent-limit 1 < "${perfdata}" > "${perfout}"
+    if ! perf annotate --code-with-type -i - --stdio 2> /dev/null --percent-limit 1 < "${perfdata}" > "${perfout}"
+    then
+      echo "${mode} annotate [Failed: perf annotate]"
+      err=1
+      return
+    fi
   fi
 
   # check if it has the target data type
-- 
2.55.0