Hello, On Tue, Feb 24, 2026 at 2:57 PM Nazir Bilal Yavuz <[email protected]> wrote:
> Hi, > > On Tue, 24 Feb 2026 at 07:44, Manni Wood <[email protected]> > wrote: > > > > Hello! > > > > I ran some speed tests on Nazir's v10 SIMD-only patch. I'm a bit > surprised at the regression for x86 with wide rows for the 1/3rd special > characters scenarios. I'm hoping it's something I did wrong. If anyone else > has numbers to share, that would be excellent. > > Thank you for doing this! > > I see similar regression on the wide & CSV 1/3 case by using your > benchmark script. I didn't see this regression when I used my > benchmark while sharing v9 [1]. > > +-------------+---------------------------+---------------------------+ > | | Text | CSV | > +-------------+-------------+-------------+-------------+-------------+ > | WIDE TEST | None | 1/3 | None | 1/3 | > +-------------+-------------+-------------+-------------+-------------+ > | Master | 9996 | 10769 | 11548 | 13960 | > +-------------+-------------+-------------+-------------+-------------+ > | v10 | 8912 %-10.8 | 10902 %+1.2 | 8952 %-22.4 | 15123 %+8.3 | > +-------------+-------------+-------------+-------------+-------------+ > | | | | | | > +-------------+-------------+-------------+-------------+-------------+ > | | Text | | CSV | > +-------------+-------------+-------------+-------------+-------------+ > | NARROW TEST | None | 1/3 | None | 1/3 | > +-------------+-------------+-------------+-------------+-------------+ > | Master | 9441 | 9561 | 9734 | 9830 | > +-------------+-------------+-------------+-------------+-------------+ > | v10 | 9291 %-1.5 | 9504 -%0.5 | 9644 %-0.9 | 10078 %-2.4 | > +-------------+-------------+-------------+-------------+-------------+ > > I will investigate this. However, please note that the current master > includes the inlining commit (dc592a4155), which makes the COPY FROM > faster. In my case, > > 1: current master without dc592a4155: 14400ms > 2: current master: 13960ms (%3 improvement against #1) > 3: current master + SIMD: 15123ms (%5 regression against #1 and %8 > regression against #2) > > Is it possible for you to do a similar test? I mean dropping > dc592a4155 from the current master and re-running the benchmark, that > would be helpful. > > [1] > https://postgr.es/m/CAN55FZ0MiFCgK26gRgE05a%3D_ggenkxDM8H%3DA2uTHpywczqt%3D-Q%40mail.gmail.com Here are some numbers for v10 from my end, these are multiple long runs: Master contains the previous inlining patch. This is on an Intel I7-1255U CPU WIDE (500k rows) TXT | none Master avg: 20,721 ms New avg: 17,980 ms Improvement: -13.23% CSV | none Master avg: 26,608 ms New avg: 18,433 ms Improvement: -30.73% TXT | escape Master avg: 25,069 ms New avg: 22,910 ms Improvement: -8.61% CSV | quote Master avg: 31,931 ms New avg: 31,493 ms Improvement: -1.37% -------------------------------------- NARROW (15M rows) TXT | none Master avg: 20,687 ms New avg: 20,824 ms Regression: +0.67% CSV | none Master avg: 21,187 ms New avg: 21,153 ms Improvement: -0.16% TXT | escape Master avg: 20,870 ms New avg: 21,341 ms Regression: +2.25% CSV | quote Master avg: 22,074 ms New avg: 22,267 ms Regression: +0.87% For narrow that would be mostly noise and extra branch effects. Regards, Ayoub
