On March 30, 2018 10:04:25 AM PDT, Konstantin Knizhnik <k.knizh...@postgrespro.ru> wrote: > > >On 30.03.2018 18:54, Andres Freund wrote: >> On 2018-03-30 15:12:05 +0300, Konstantin Knizhnik wrote: >>> I have repeated performance tests at my computer and find out some >>> regression comparing with previous JIT version. >>> Previously JIT provides about 2 times improvement at TPC-H Q1. Now >the >>> difference is reduced to 1.4 without parallel execution and 1.3 with >>> parallel execution: >> Huh. That's the same computer you did the tests on? >> >> There shouldn't have been any, I'll check it out. >> >> - Andres > >Yes, it is the same computer. >But sorry, may be it is false alarm. >I noticed that the time of normal (non-jit) query execution was also >faster in the past: for parallel execution 6549 vs. 7550 now, for >non-parallel execution 20075 vs. 25100. >I do not know whether this difference is caused by some changes in >Postgres committed since this time (end of January) or just because of >different layout of data in memory.
A brief attempt at bisecting would be good. That's quite the regression. Possibly it's OS related though. Meltdown / Spectre? Andres -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
