On 2014-04-16 19:18:02 -0400, Bruce Momjian wrote: > On Thu, Feb 6, 2014 at 09:40:32AM +0100, Andres Freund wrote: > > On 2014-02-05 12:36:42 -0500, Robert Haas wrote: > > > >> It may well be that your proposal is spot on. But I'd like to see some > > > >> data-structure-by-data-structure measurements, rather than assuming > > > >> that > > > >> alignment must be a good thing. > > > > > > > > I am fine with just aligning BufferDescriptors properly. That has > > > > clearly shown massive improvements. > > > > > > I thought your previous idea of increasing BUFFERALIGN to 64 bytes had > > > a lot to recommend it. > > > > Good. > > > > I wonder if we shouldn't move that bit of logic: > > if (size >= BUFSIZ) > > newStart = BUFFERALIGN(newStart); > > out of ShmemAlloc() and instead have a ShmemAllocAligned() and > > ShmemInitStructAligned() that does it. So we can sensibly can control it > > per struct. > > > > > But that doesn't mean it doesn't need testing. > > > > I feel the need here, to say that I never said it doesn't need testing > > and never thought it didn't... > > Where are we on this?
It needs somebody with time to evaluate possible performance regressions - I personally won't have time to look into this in detail before pgcon. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers