From ac803a69c8d04c266fa32f2a89bc61750f0775b2 Mon Sep 17 00:00:00 2001 From: Thomas Richter Date: Mon, 29 Nov 2021 12:23:39 +0100 Subject: [PATCH] perf test: Fix 'Simple expression parser' test on arch without CPU die topology info Some platforms do not have CPU die support, for example s390. Commit Cc: Ian Rogers Fixes: e896a2cb3d0f79b0 ("perf expr: Add metric literals for topology.") fails on s390: # perf test -Fv 7 ... # FAILED tests/expr.c:173 #num_dies >= #num_packages ---- end ---- Simple expression parser: FAILED! # Investigating this issue leads to these functions: build_cpu_topology() +--> has_die_topology(void) { struct utsname uts; if (uname(&uts) < 0) return false; if (strncmp(uts.machine, "x86_64", 6)) return false; .... } which always returns false on s390. The caller build_cpu_topology() checks has_die_topology() return value. On false the the struct cpu_topology::die_cpu_list is not contructed and has zero entries. This leads to the failing comparison: #num_dies >= #num_packages. s390 of course has a positive number of packages. Fix this and check if the function build_cpu_topology() did build up a die_cpus_list. The number of entries in this list should be larger than 0. If the number of list element is zero, the die_cpus_list has not been created and the check in function test__expr(): TEST_ASSERT_VAL("#num_dies >= #num_packages", \ num_dies >= num_packages) always fails. Output after: # perf test -Fv 7 7: Simple expression parser : --- start --- division by zero syntax error ---- end ---- Simple expression parser: Ok # Fixes: e896a2cb3d0f79b0 ("perf expr: Add metric literals for topology.") Signed-off-by: Thomas Richter Acked-by: Ian Rogers Cc: Heiko Carstens Cc: Sumanth Korikkar Cc: Sven Schnelle Cc: Vasily Gorbik Link: http://lore.kernel.org/lkml/20211129112339.3003036-1-tmricht@linux.ibm.com [ Added comment in the added 'if (num_dies)' line about architectures not having die topology ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/tests/expr.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c index c895de481fe10..d54c5371c6a6e 100644 --- a/tools/perf/tests/expr.c +++ b/tools/perf/tests/expr.c @@ -169,7 +169,9 @@ static int test__expr(struct test_suite *t __maybe_unused, int subtest __maybe_u TEST_ASSERT_VAL("#num_dies", expr__parse(&num_dies, ctx, "#num_dies") == 0); TEST_ASSERT_VAL("#num_cores >= #num_dies", num_cores >= num_dies); TEST_ASSERT_VAL("#num_packages", expr__parse(&num_packages, ctx, "#num_packages") == 0); - TEST_ASSERT_VAL("#num_dies >= #num_packages", num_dies >= num_packages); + + if (num_dies) // Some platforms do not have CPU die support, for example s390 + TEST_ASSERT_VAL("#num_dies >= #num_packages", num_dies >= num_packages); /* * Source count returns the number of events aggregating in a leader -- 2.39.5