Andres Freund <and...@2ndquadrant.com> writes: > So, what we do is we guarantee that LWLocks are aligned to 16 or 32byte > boundaries. That means that on x86-64 (64byte cachelines, 24bytes > unpadded lwlock) two lwlocks share a cacheline.
Yup. > In my benchmarks changing the padding to 64byte increases performance in > workloads with contended lwlocks considerably. At a huge cost in RAM. Remember we make two LWLocks per shared buffer. I think that rather than using a blunt instrument like that, we ought to see if we can identify pairs of hot LWLocks and make sure they're not adjacent. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers