On 24 February 2016 at 23:26, Amit Kapila <amit.kapil...@gmail.com> wrote:
> From past few weeks, we were facing some performance degradation in the > read-only performance bench marks in high-end machines. My colleague > Mithun, has tried by reverting commit ac1d794 which seems to degrade the > performance in HEAD on high-end m/c's as reported previously[1], but still > we were getting degradation, then we have done some profiling to see what > has caused it and we found that it's mainly caused by spin lock when > called via pin/unpin buffer and then we tried by reverting commit 6150a1b0 > which has recently changed the structures in that area and it turns out > that reverting that patch, we don't see any degradation in performance. > The important point to note is that the performance degradation doesn't > occur every time, but if the tests are repeated twice or thrice, it > is easily visible. > Not seen that on the original patch I posted. 6150a1b0 contains multiple changes to the lwlock structures, one written by me, others by Andres. Perhaps we should revert that patch and re-apply the various changes in multiple commits so we can see the differences. -- Simon Riggs http://www.2ndQuadrant.com/ <http://www.2ndquadrant.com/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
