On Sun, Nov 02, 2014 at 10:17:26PM +0100, Attilio Rao wrote: > On Sun, Nov 2, 2014 at 8:10 PM, Konstantin Belousov <kostik...@gmail.com> > wrote: > > On Sun, Nov 02, 2014 at 06:53:44PM +0100, Attilio Rao wrote: > >> > I did not proposed to verify owner chain. I said that it is easy to > >> > record the locks owned by current thread, only for current thread > >> > consumption. Below is the prototype. > >> > >> I think it is too expensive, think that this must happen for every shared > >> lock. > >> I know we may not be using too many shared locks on lockmgr right now, > >> but it is not a good reason to make shared lock bloated and more > >> expensive on lockmgr. > > > > It can be significantly simplified, if the array of lock pointers is > > kept dense. Then the only non-trivial operation is unlock out of order, > > when the array have to be compacted. > > > > The code adds one write and n reads on shared lock, where n is the > > number of shared-locked locks already owned by thread. Typical n is 0 > > or 1. On unlock, if done in order, the code adds one read; unordered > > unlock shuffles array elements. Again, for typical lock nesting of 2, > > this means one read and one write, and even this is rare. All reads and > > writes are for thread-local memory. > > > > I am not going to spend any more time on this if people do not consider > > the lock tracking worth it. Otherwise, I will benchmark the patch. > > I think that your initial patch (what is in head now) is a better approach. > I would just make it a lockinit() flag to make it less alien to the KPI. >
Ok. Can you explain what would the proposed lockinit() flag do ? What should it change comparing with the current code ? _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
