On Fri, Dec 19, 2008 at 04:19:11PM +0900, KAMEZAWA Hiroyuki wrote: > Result of cost-of-fork() on ia64. > == > size of memory before after > Anon=1M , 0.07ms, 0.08ms > Anon=10M , 0.17ms, 0.22ms > Anon=100M , 1.15ms, 1.64ms > Anon=1000M , 11.5ms, 15.821ms > == > > fork() cost is 135% when the process has 1G of Anon. Not sure where the 135% number comes from. The above number shows a performance decrease of 27% or a time increase of 37% which I hope is inline with the overhead introduced by the TestSetPageLocked in the fast path (which I didn't expect to be so bad), but that it's almost trivial to eliminate with a smb_wmb in add_to_swap_cache and a smb_rmb in fork. So we'll need to repeat this measurement after replacing the TestSetPageLocked with smb_rmb. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
