On Fri, 2 Oct 2020 01:06:21 -0700 John Hubbard <jhubb...@nvidia.com> wrote:
> 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.) Seems nice. It's been 5 years, but hopefully Sri is still at Akamai? > --- 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) { > -- > 2.28.0 >