On 2016-03-28 11:48:46 +0530, Dilip Kumar wrote: > On Sun, Mar 27, 2016 at 5:48 PM, Andres Freund <and...@anarazel.de> wrote: > > > > > What's sizeof(BufferDesc) after applying these patches? It should better > > be <= 64... > > > > It is 72.
Ah yes, miscalculated the required alignment. Hm. So we got to get this smaller. I see three approaches: 1) Reduce the spinlock size on ppc. That actually might just work by replacing "unsigned int" by "unsigned char" 2) Replace the lwlock spinlock by a bit in LWLock->state. That'd avoid embedding the spinlock, and actually might allow to avoid one atomic op in a number of cases. 3) Shrink the size of BufferDesc by removing buf_id; that'd bring it to 64byte. I'm a bit hesitant to go for 3), because it'd likely end up adding a bit of arithmetic to a number of places in bufmgr.c. Robert, what do you think? Andres -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers