Without -O2, the generated code for testing chacha function is awful.
GCC even implements rol32() as a function instead of just using the
rotlwi instruction, that function is 20 instructions long.
~# time ./vdso_test_chacha
TAP version 13
1..1
ok 1 chacha: PASS
real 0m 37.16s
user 0m 36.89s
sys 0m 0.26s
Several other selftests directory add -O2, and the kernel is also
always built with optimisation active. Do the same for vDSO selftests.
With this patch the time is reduced by approx 15%.
~# time ./vdso_test_chacha
TAP version 13
1..1
ok 1 chacha: PASS
real 0m 32.09s
user 0m 31.86s
sys 0m 0.22s
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
tools/testing/selftests/vDSO/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/vDSO/Makefile
b/tools/testing/selftests/vDSO/Makefile
index cfb7c281b22c..96f25aa2f84e 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -13,7 +13,7 @@ TEST_GEN_PROGS += vdso_test_correctness
TEST_GEN_PROGS += vdso_test_getrandom
TEST_GEN_PROGS += vdso_test_chacha
-CFLAGS := -std=gnu99
+CFLAGS := -std=gnu99 -O2
ifeq ($(CONFIG_X86_32),y)
LDLIBS += -lgcc_s
--
2.44.0
