Hi, On 2015-09-06 14:10:24 +0100, Simon Riggs wrote: > It separates the Buffer LWLocks from the main LW locks, allowing them to > have different padding. > > Tests showed noticeable/significant performance gain due to reduced false > sharing on main LWlocks, though without wasting memory on the buffer > LWlocks.
Hm. I found that the buffer content lwlocks can actually also be a significant source of contention - I'm not sure reducing padding for those is going to be particularly nice. I think we should rather move the *content* lock inline into the buffer descriptor. The io lock doesn't matter and can be as small as possible. Additionally I think we should increase the lwlock padding to 64byte (i.e. the by far most command cacheline size). In the past I've seen that to be rather beneficial. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
