On Wed, Oct 11, 2017 at 02:01:51PM -0400, Waiman Long wrote: > # of Patches Reader Writer > Applied Locking Rate Locking Rate > ------------ ------------ ------------ > 0 5,155/ 5,155/ 5,155 5,154/248,852/346,281 > 7 5,696/ 5,697/ 5,698 113,500/215,826/320,872 > 8 4,827/ 5,047/ 5,215 4,826/176,797/284,069 > 9 211,276/ 509,712/1,134,007 4,894/221,839/246,818 > 11 884,513/1,043,989/1,252,533 9,604/ 11,105/ 25,225 > > It can be seen that rwsem changes from writer-preferring to > reader-preferring.
A bit radically so, you almost starve the writers there.
