On 4/14/25 04:09, David Rowley wrote: > I noticed a while ago that the new fast-path locking code uses integer > division to figure out the fast-path locking group slot. To me, this > seems a bit unnecessary as FastPathLockGroupsPerBackend is always a > power-of-two value, so we can use bitwise-AND instead. > > I don't think FAST_PATH_REL_GROUP() is in any particularly hot code > paths, but still, having the divide in there isn't sitting well with > me. Can we get rid of it? >
Yes, we can get rid of the divide - if we assume power-of-two value (which seems fine, we already do that, IIRC). > I've attached a patch for that. I also adjusted the method used to > calculate FastPathLockGroupsPerBackend. Also, the Assert that was > going on at the end of the loop in InitializeFastPathLocks() looked a > little odd as it seems to be verifying something that the loop > condition was checking already. I thought it was better to check that > we end up with a power-of-two. > > Please see the attached patch. > Thanks. Those changes seem fine to me to. Do you intend to push these, or do you want me to do it? regards -- Tomas Vondra
