mirror_ubuntu-kernels/tools/testing
Dev Jain c7876a0cc6 selftests/mm: mremap_test: optimize using pre-filled random array and memcpy
Patch series "selftests/mm: mremap_test: Optimizations and style fixes".

The mremap_test, in a worst case controlled by the -t flag, does a for
loop iteration in orders of GB.  Without compromising on the stdout
report, the aim is to reduce this time.

A pre-filled random buffer is allocated based on the seed, replacing
repetitive rand() calls.  The byte pattern in the memory locations is set
through memcpy() from the random buffer.

Replacing the loop for printing the mismatch index to stdout, employ an
efficient algorithm by breaking the comparison into chunks, use the highly
optimized memcmp() library function, and when a mismatch does occur, only
then do a brute force iteration.

Also, use sscanf() to parse /proc/self/maps for consistency across files.

Execution time results (x86 system):
./mremap_test
Original: 3 seconds
After change: 0.8 seconds

./mremap_test -t100
Original: 17 seconds
After change: 2 seconds

./mremap_test -t0 (worst case):
Original: 9:40 minutes
After change: 45 seconds


This patch (of 3):

Allocate a pre-filled random buffer using the seed.  Replace iterative
copying of the random sequence to buffers using the highly optimized
library function memcpy().

Link: https://lkml.kernel.org/r/20240330173557.2697684-1-dev.jain@arm.com
Link: https://lkml.kernel.org/r/20240330173557.2697684-2-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:56:32 -07:00
..
crypto/chacha20-s390
cxl cxl: Consolidate dport access_coordinate ->hb_coord and ->sw_coord into ->coord 2024-04-08 08:25:21 -07:00
fault-injection
ktest ktest: force $buildonly = 1 for 'make_warnings_file' test type 2024-03-15 12:36:19 -04:00
kunit linux_kselftest-kunit-fixes-6.9-rc2 2024-03-29 15:35:12 -07:00
memblock mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
nvdimm tools/testing/nvdimm: Disable "missing prototypes / declarations" warnings 2024-01-22 10:41:59 -08:00
radix-tree maple_tree: fix warning comparing pointer to 0 2023-12-20 14:48:12 -08:00
scatterlist
selftests selftests/mm: mremap_test: optimize using pre-filled random array and memcpy 2024-04-25 20:56:32 -07:00
vsock vsock/test: print type for SOCK_SEQPACKET 2024-01-25 16:39:21 -08:00