On Fri, Feb 02, 2024 at 04:33:04PM +0800, JonasZhou-oc wrote: > From: JonasZhou <JonasZhou@xxxxxxxxxxx> > > In the struct address_space, there is a 32-byte gap between i_mmap > and i_mmap_rwsem. Due to the alignment of struct address_space > variables to 8 bytes, in certain situations, i_mmap and i_mmap_rwsem > may end up in the same CACHE line. > > While running Unixbench/execl, we observe high false sharing issues > when accessing i_mmap against i_mmap_rwsem. We move i_mmap_rwsem > after i_private_list, ensuring a 64-byte gap between i_mmap and > i_mmap_rwsem. > > For Intel Silver machines (2 sockets) using kernel v6.8 rc-2, the score > of Unixbench/execl improves by ~3.94%, and the score of Unixbench/shell > improves by ~3.26%. Looks sane.
