On 2013-11-15 20:47:26 +0100, Andres Freund wrote: > Hi, > > On 2013-09-27 00:55:45 +0200, Andres Freund wrote: > > So what's todo? The file header tells us: > > * - revive pure-spinlock implementation > > * - abstract away atomic ops, we really only need a few. > > * - CAS > > * - LOCK XADD > > * - convert PGPROC->lwWaitLink to ilist.h slist or even dlist. > > * - remove LWLockWakeup dealing with MyProc > > * - overhaul the mask offsets, make SHARED/EXCLUSIVE_LOCK_MASK wider, > > MAX_BACKENDS > > So, here's the next version of this patchset: > 1) I've added an abstracted atomic ops implementation. Needs a fair > amount of work, also submitted as a separate CF entry. (Patch 1 & 2) > 2) I've converted PGPROC->lwWaiting into a dlist. That makes a fair bit > of code easier to read and reduces the size of the patchset. Also > fixes a bug in the xlog-scalability code. (Patch 3) > 3) Alvaro and I updated the comments in lwlock.c. (Patch 4) > > I think 2) should be committable pretty soon. It's imo a pretty clear > win in readability. 1) will need a good bit of more work. > > With regard to the scalable lwlock work, what's most needed now is a > good amount of testing. > > Please note that you need to 'autoreconf' after applying the patchset. I > don't have a compatible autoconf version on this computer causing the > diff to be humongous if I include those changes.
Please also note that due to the current state of the atomics implementation this likely will only work on a somewhat recent gcc and that the performance might be slightly worse than in the previous version because the atomic add is implemented using the CAS fallback. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
