Bruce Momjian <pgman@candle.pha.pa.us> writes: > And ARC has locking requirements that will make it very hard to fix our > SMP buffer management problems in 8.1.
I am working on a buffer manager rewrite using the BufMgrLock breakup and "clock sweep" management algorithm we've been discussing. At the moment it's passing the regression tests but I'm sure there's some bugs left :-(. I just now tried it on the infamous context-swap-storm test case using a 4-way machine at Red Hat. PG 8.0 shows 20K or more CS/sec and under 30% CPU usage in this situation. The patch shows 99% CPU utilization and about 200 CS/sec (which is about nil, because the machine shows ~100 CS/sec with nothing running except vmstat). Still to be determined: what we lose in extra I/O from the presumably less efficient cache management; also what sort of slowdown occurs on a single-CPU machine that isn't going to get any benefit from the increased amount of lock management. But it looks promising. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org