linux/tools
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
..
accounting
arch LoongArch changes for v6.9 2024-03-22 10:22:45 -07:00
bootconfig
bpf libbpf, selftests/bpf: Adjust libbpf, bpftool, selftests to match LLVM 2024-03-15 14:24:00 -07:00
build
certs
cgroup proc: rewrite stable_page_flags() 2024-04-25 20:56:15 -07:00
counter
crypto
debugging
firewire
firmware
gpio
hv hv/hv_kvp_daemon: Handle IPv4 and Ipv6 combination for keyfile format 2024-04-10 21:25:40 +00:00
iio
include memblock tests: fix build errors 2024-04-08 10:11:37 -07:00
kvm/kvm_stat
laptop
leds
lib bpf-for-netdev 2024-03-26 12:55:18 +01:00
memory-model
mm
net/ynl tools: ynl: fix setting presence bits in simple nests 2024-03-22 17:54:38 -07:00
objtool objtool: Fix compile failure when using the x32 compiler 2024-03-30 22:12:37 +01:00
pci
pcmcia
perf RISC-V Patches for the 6.9 Merge Window 2024-03-22 10:41:13 -07:00
power Turbostat version 2024.04.10 2024-04-10 13:13:27 -07:00
rcu
scripts
spi
testing selftests/mm: mremap_test: optimize using pre-filled random array and memcpy 2024-04-25 20:56:32 -07:00
thermal
time
tracing tools/rtla: Add -U/--user-load option to timerlat 2024-03-20 05:39:06 +01:00
usb
verification tools/verification: Use tools/build makefiles on rv 2024-03-20 05:39:06 +01:00
virtio tools: virtio: introduce vhost_net_test 2024-03-05 11:38:14 +01:00
wmi
workqueue
Makefile tools/Makefile: remove cgroup target 2024-03-26 11:07:21 -07:00