On Mon, Mar 28, 2016 at 9:09 AM, Andres Freund <and...@anarazel.de> wrote: > 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?
I don't have a clear idea what's going to be better here. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
