[PATCH] perf tests: Fix indexing when invoking subtests

[Sandipan Das]

Recently, the subtest numbering was changed to start from 1.
While it is fine for displaying results, this should not be
the case when the subtests are actually invoked.

Typically, the subtests are stored in zero-indexed arrays and
invoked based on the index passed to the main test function.
Since the index now starts from 1, the second subtest in the
array (index 1) gets invoked instead of the first (index 0).
This applies to all of the following subtests but for the last
one, the subtest always fails because it does not meet the
boundary condition of the subtest index being lesser than the
number of subtests.

This can be observed on powerpc64 and x86_64 systems running
Fedora 28 as shown below.

Before:

  # perf test "builtin clang support"
  55: builtin clang support                                 :
  55.1: builtin clang compile C source to IR                : Ok
  55.2: builtin clang compile C source to ELF object        : FAILED!

  # perf test "LLVM search and compile"
  38: LLVM search and compile                               :
  38.1: Basic BPF llvm compile                              : Ok
  38.2: kbuild searching                                    : Ok
  38.3: Compile source for BPF prologue generation          : Ok
  38.4: Compile source for BPF relocation                   : FAILED!

  # perf test "BPF filter"
  40: BPF filter                                            :
  40.1: Basic BPF filtering                                 : Ok
  40.2: BPF pinning                                         : Ok
  40.3: BPF prologue generation                             : Ok
  40.4: BPF relocation checker                              : FAILED!

After:

  # perf test "builtin clang support"
  55: builtin clang support                                 :
  55.1: builtin clang compile C source to IR                : Ok
  55.2: builtin clang compile C source to ELF object        : Ok

  # perf test "LLVM search and compile"
  38: LLVM search and compile                               :
  38.1: Basic BPF llvm compile                              : Ok
  38.2: kbuild searching                                    : Ok
  38.3: Compile source for BPF prologue generation          : Ok
  38.4: Compile source for BPF relocation                   : Ok

  # perf test "BPF filter"
  40: BPF filter                                            :
  40.1: Basic BPF filtering                                 : Ok
  40.2: BPF pinning                                         : Ok
  40.3: BPF prologue generation                             : Ok
  40.4: BPF relocation checker                              : Ok

Fixes: 9ef0112442bd ("perf test: Fix subtest number when showing results")
Signed-off-by: Sandipan Das <sandipan@xxxxxxxxxxxxx>
---
 tools/perf/tests/builtin-test.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 4f5de8245b32..d7a5e1b9aa6f 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -385,7 +385,7 @@ static int test_and_print(struct test *t, bool force_skip, int subtest)
 	if (!t->subtest.get_nr)
 		pr_debug("%s:", t->desc);
 	else
-		pr_debug("%s subtest %d:", t->desc, subtest);
+		pr_debug("%s subtest %d:", t->desc, subtest + 1);
 
 	switch (err) {
 	case TEST_OK:
@@ -599,7 +599,7 @@ static int __cmd_test(int argc, const char *argv[], struct intlist *skiplist)
 			for (subi = 0; subi < subn; subi++) {
 				pr_info("%2d.%1d: %-*s:", i, subi + 1, subw,
 					t->subtest.get_desc(subi));
-				err = test_and_print(t, skip, subi + 1);
+				err = test_and_print(t, skip, subi);
 				if (err != TEST_OK && t->subtest.skip_if_fail)
 					skip = true;
 			}
-- 
2.14.4