lib: test module for find_*_bit() functions
find_bit functions are widely used in the kernel, including hot paths.
This module tests performance of those functions in 2 typical scenarios:
randomly filled bitmap with relatively equal distribution of set and
cleared bits, and sparse bitmap which has 1 set bit for 500 cleared
bits.
On ThunderX machine:
Start testing find_bit() with random-filled bitmap
find_next_bit: 240043 cycles, 164062 iterations
find_next_zero_bit: 312848 cycles, 163619 iterations
find_last_bit: 193748 cycles, 164062 iterations
find_first_bit: 177720874 cycles, 164062 iterations
Start testing find_bit() with sparse bitmap
find_next_bit: 3633 cycles, 656 iterations
find_next_zero_bit: 620399 cycles, 327025 iterations
find_last_bit: 3038 cycles, 656 iterations
find_first_bit: 691407 cycles, 656 iterations
[arnd@arndb.de: use correct format string for find-bit tests]
Link: http://lkml.kernel.org/r/20171113135605.3166307-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20171109140714.13168-1-ynorov@caviumnetworks.com
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Clement Courbet <courbet@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/Makefile b/lib/Makefile
index e3cb2a2..d11c48e 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -47,6 +47,7 @@
obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o
obj-y += kstrtox.o
obj-$(CONFIG_TEST_BPF) += test_bpf.o
+obj-$(CONFIG_TEST_FIND_BIT) += test_find_bit.o
obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o
obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o