On 2015-08-04 11:43:45 -0400, Robert Haas wrote: > On Tue, Aug 4, 2015 at 11:33 AM, Andres Freund <and...@anarazel.de> wrote: > > Actually by far not all system calls are full barriers? > > How do we know which ones are and which ones are not?
Good question. Reading the source code of all implementations I suppose :( E.g. gettimeofday()/clock_gettime(), getpid() on linux aren't barriers. > I can't believe PGSemaphoreUnlock isn't a barrier. That would be cruel. Yea, I think that's a pretty safe bet. I mean even if you'd implement it locklessly in the kernel, that'd still employ significant enough barriers/atomic ops itself. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
