From 1100262037be8008cc85240389fbe5eac4df034d Mon Sep 17 00:00:00 2001 From: John Hubbard Date: Tue, 13 Oct 2020 16:57:04 -0700 Subject: [PATCH] selftests/vm: 8x compaction_test speedup This patch reduces the running time for compaction_test from about 27 sec, to 3.3 sec, which is about an 8x speedup. These numbers are for an Intel x86_64 system with 32 GB of DRAM. The compaction_test.c program was spending most of its time doing mmap(), 1 MB at a time, on about 25 GB of memory. Instead, do the mmaps 100 MB at a time. (Going past 100 MB doesn't make things go much faster, because other parts of the program are using the remaining time.) Signed-off-by: John Hubbard Signed-off-by: Andrew Morton Acked-by: Sri Jayaramappa Cc: Shuah Khan Cc: Mel Gorman Link: https://lkml.kernel.org/r/20201002080621.551044-2-jhubbard@nvidia.com Signed-off-by: Linus Torvalds --- tools/testing/selftests/vm/compaction_test.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/vm/compaction_test.c b/tools/testing/selftests/vm/compaction_test.c index bcec71250873..9b420140ba2b 100644 --- a/tools/testing/selftests/vm/compaction_test.c +++ b/tools/testing/selftests/vm/compaction_test.c @@ -18,7 +18,8 @@ #include "../kselftest.h" -#define MAP_SIZE 1048576 +#define MAP_SIZE_MB 100 +#define MAP_SIZE (MAP_SIZE_MB * 1024 * 1024) struct map_list { void *map; @@ -165,7 +166,7 @@ int main(int argc, char **argv) void *map = NULL; unsigned long mem_free = 0; unsigned long hugepage_size = 0; - unsigned long mem_fragmentable = 0; + long mem_fragmentable_MB = 0; if (prereq() != 0) { printf("Either the sysctl compact_unevictable_allowed is not\n" @@ -190,9 +191,9 @@ int main(int argc, char **argv) return -1; } - mem_fragmentable = mem_free * 0.8 / 1024; + mem_fragmentable_MB = mem_free * 0.8 / 1024; - while (mem_fragmentable > 0) { + while (mem_fragmentable_MB > 0) { map = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0); if (map == MAP_FAILED) @@ -213,7 +214,7 @@ int main(int argc, char **argv) for (i = 0; i < MAP_SIZE; i += page_size) *(unsigned long *)(map + i) = (unsigned long)map + i; - mem_fragmentable--; + mem_fragmentable_MB -= MAP_SIZE_MB; } for (entry = list; entry != NULL; entry = entry->next) { -- GitLab