perf tests stat+json_output: Include sanity check for topology

Testcase stat+json_output.sh fails in powerpc:

86: perf stat JSON output linter : FAILED!

The testcase "stat+json_output.sh" verifies perf stat JSON output. The
test covers aggregation modes like per-socket, per-core, per-die, -A
(no_aggr mode) along with few other tests. It counts expected fields for
various commands. For example say -A (i.e, AGGR_NONE mode), expects 7
fields in the output having "CPU" as first field. Same way, for
per-socket, it expects the first field in result to point to socket id.
The testcases compares the result with expected count.

The values for socket, die, core and cpu are fetched from topology
directory:

/sys/devices/system/cpu/cpu*/topology.

For example, socket value is fetched from "physical_package_id" file of
topology directory. (cpu__get_topology_int() in util/cpumap.c)

If a platform fails to fetch the topology information, values will be
set to -1. For example, incase of pSeries platform of powerpc, value for
"physical_package_id" is restricted and not exposed. So, -1 will be
assigned.

Perf code has a checks for valid cpu id in "aggr_printout"
(stat-display.c), which displays the fields. So, in cases where topology
values not exposed, first field of the output displaying will be empty.
This cause the testcase to fail, as it counts number of fields in the
output.

Incase of -A (AGGR_NONE mode,), testcase expects 7 fields in the output,
becos of -1 value obtained from topology files for some, only 6 fields
are printed. Hence a testcase failure reported due to mismatch in number
of fields in the output.

Patch here adds a sanity check in the testcase for topology. Check will
help to skip the test if -1 value found.

Fixes: 0c343af2a2f82844 ("perf test: JSON format checking")
Reported-by: Disha Goel <[e-mail]>
Suggested-by: Ian Rogers <[e-mail]>
Suggested-by: James Clark <[e-mail]>
Signed-off-by: Athira Jajeev <[e-mail]>
Cc: Claire Jensen <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: [e-mail]
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Nageswara R Sastry <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/shell/stat+json_output.sh

···
 
 set -e
 
+skip_test=0
+
 pythonchecker=$(dirname $0)/lib/perf_json_output_lint.py
 if [ "x$PYTHON" == "x" ]
 then
···
 	echo "[Success]"
 }
 
+# The perf stat options for per-socket, per-core, per-die
+# and -A ( no_aggr mode ) uses the info fetched from this
+# directory: "/sys/devices/system/cpu/cpu*/topology". For
+# example, socket value is fetched from "physical_package_id"
+# file in topology directory.
+# Reference: cpu__get_topology_int in util/cpumap.c
+# If the platform doesn't expose topology information, values
+# will be set to -1. For example, incase of pSeries platform
+# of powerpc, value for  "physical_package_id" is restricted
+# and set to -1. Check here validates the socket-id read from
+# topology file before proceeding further
+
+FILE_LOC="/sys/devices/system/cpu/cpu*/topology/"
+FILE_NAME="physical_package_id"
+
+check_for_topology()
+{
+	if ! ParanoidAndNotRoot 0
+	then
+		socket_file=`ls $FILE_LOC/$FILE_NAME | head -n 1`
+		[ -z $socket_file ] && return 0
+		socket_id=`cat $socket_file`
+		[ $socket_id == -1 ] && skip_test=1
+		return 0
+	fi
+}
+
+check_for_topology
 check_no_args
 check_system_wide
-check_system_wide_no_aggr
 check_interval
 check_event
-check_per_core
 check_per_thread
-check_per_die
 check_per_node
-check_per_socket
+if [ $skip_test -ne 1 ]
+then
+	check_system_wide_no_aggr
+	check_per_core
+	check_per_die
+	check_per_socket
+else
+	echo "[Skip] Skipping tests for system_wide_no_aggr, per_core, per_die and per_socket since socket id exposed via topology is invalid"
+fi
 exit 0