QSBR

[ibraheemdev]

Applications that are constantly entering and leaving are marking threads as active/inactive for no reason; there is little benefit if threads are active 99% of the time. We could instead make enter a no-op (a big win) and have leave not mark threads as inactive (effectively become flush), acting more like QSBR.

[ibraheemdev]

Making threads always active is problematic because threads do not necessarily need to call leave before exiting, which could leak memory. Without a global collector we can't really deal with leaked threads. Using process-wide barriers (see: membarrier) could improve enter performance enough to make this unnecessary (by allowing the store of active to be relaxed).