On Thu, Jul 21, 2011 at 6:43 PM, Noah Misch <n...@2ndquadrant.com> wrote: > On Wed, Jul 20, 2011 at 09:46:33PM -0400, Robert Haas wrote: >> Profiling this combination of patches reveals that there is still some >> pretty ugly spinlock contention on sinval's msgNumLock. And it occurs >> to me that on x86, we really don't need this lock ... or >> SInvalReadLock ... or a per-backend mutex. The whole of >> SIGetDataEntries() can pretty easily be made lock-free. The only real >> changes that seem to be are needed are (1) to use a 64-bit counter, so >> you never need to decrement > > On second thought, won't this be inadequate on 32-bit systems, where updating > the 64-bit counter produces two stores? You must avoid reading it between > those > stores.
Now that is a potentially big problem. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
