On Saturday, November 26, 2011 11:39:23 PM Robert Haas wrote: > On Sat, Nov 26, 2011 at 5:28 PM, Andres Freund <and...@anarazel.de> wrote: > > On Saturday, November 26, 2011 09:52:17 PM Tom Lane wrote: > >> I'd just as soon keep the fields in a logical order. > > > > Btw, I don't think the new order is necessarily worse than the old one. > > You forget to attach the benchmark results. > > My impression is that cache lines on modern hardware are 64 or 128 > *bytes*, in which case this wouldn't matter a bit. All current x86 cpus use 64bytes. The 2nd 128bit reference was a typo. Sorry for that. And why is 72=>56 *bytes* (I even got that one right) not relevant for 64byte cachelines?
And yea. I didn't add benchmark results. I don't think I *have* to do that when making suggestions to somebody trying to improve something specific. I also currently don't have hardware where I can sensibly run at a high enough concurrency to see that GetSnapshotData takes ~40% of runtime. Additional cacheline references around synchronized access can hurt to my knowledge... Andres -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
