VM-I/O concurrency project for FreeBSD 10.0-Release

This page documents proposed task-list for improving VM subsystem and I/O stack concurrency and performance to be delivered in FreeBSD 10.0-Release. Everyone is encouraged in modifying the page adding more tasks, submitting his name under projects to be completed and offer guidance, review and testing for any of these items.

Task	Responsible	Last update	Status / % complete	Location of branch
~~Multi-digit trie and use it for resident and cached pages within vm_objects~~	attilio	03/17/2013	Completed (r248449 et al.)
~~Unmapped I/O~~	jeff, kib	03/18/2013	Completed (r246713,248280 et al.)
~~radix tree for buf cache~~	jeff	04/29/2013	Completed
~~vfs_bio.c mtx contention bqlock~~	jeff	03/10/2013	Completed
Fine-grained locking for pv lists	alc	06/03/2013	FineGrainedPvListsPmap 75% Complete (r235695, r237228, r237290, r237551, r237592)
Shared locking for vm_objects lock	attilio, alc	12/21/2012	In progress	svn://svn.freebsd.org/base/user/attilio/vmobj-readlock/
Fine-grained locking for active and inactive page queues	alc, kib	12/21/2012	In progress	https://www.kib.kiev.ua/git/gitweb.cgi?p=deviant2.git;a=shortlog;h=refs/heads/nofault
Fine-grained locking for free pages queue	alc, jeff	12/21/2012	In progress
Improved kernel NUMA support	jeff, alc, attilio	12/21/2012	In progress

Task	Responsible	Last update	Status / % complete
Unmapped I/O exploiting by non-critical CAM drivers	???	12/21/2012
Implement userland NUMA support	jeff, alc, attilio	12/21/2012	Unstarted
GEOM multi-threading dispatching	mav	10/22/2013	Completed (r256880+)
Revisit GEOM BIOs copy overhead	pjd	12/21/2012	Unstarted
SMP CAM/CAM multithreading - Fix CAM consumers to not assume GEOM single-threading	mav	10/21/2013	Completed (r256843+)
so_snd/so_rcv contention	???	03/10/2013	Unstarted
umtx/pthread overhaul	attilio, davide	03/22/2013	Unstarted
unmapped mbufs	jeffr	NA/NA	Unstarted