[Linux-ia64] munmap() slowness

Andy Isaacson
2003-03-05T23:30:01Z

munmap on a 15TB anonymous area is extremely slow on our Itanium 2 box.

#include <sys/mman.h>
int main(void) {
size_t s = 1024*1024*1024*1024L * 15;
munmap(mmap(0, s, PROT_READ|PROT_WRITE,
MAP_NORESERVE|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0),
s);
return 0;
}

./a.out 0.00s user 1.51s system 100% cpu 1.515 total

The kernel is 2.4.19 plus linux-2.4.19-ia64-020821.diff.gz (plus some
local changes that shouldn't be relevant).

Of course this isn't a real app, but I thought this was an interesting
result.

Please CC me on any replies, as I am not subscribed to the list.

-andy