Hi All,
I checked with LLVM/CLang 14.0 on arch x86-64-O3 in the Mac/AMD EPYC
environment , but I see GCC performs better than Clang14.
Clang14-https://github.com/llvm/llvm-project(main branch and pull or
commitID:3f3fe4a5cfa1797..)
[image: image.png]
pre analysis GCC vs Clang
(1) GCC more inline
> GCC vs Clang
related:
As I see - with LLVM/Clang 14.0 ( X86_64 -O3 ) ~12% performance increase
expected with the new optimisation ( probably adapted from gcc )
- https://twitter.com/djtodoro/status/1466808507240386560
-
https://www.phoronix.com/scan.php?page=news_item&px=LLVM-Clang-14-Hoist-L
Yes, currently focusing affects queries as well.
In meanwhile on analysis(hardware level) and sample examples noticed
1. GCC performance better than Clang on int128 .
2. Clang performance better than GCC on long long
the reference example
https://stackoverflow.com/questions/63029428/why-is-int128
Hi,
IMO this thread provides so little information it's almost impossible to
answer the question. There's almost no information about the hardware,
scale of the test, configuration of the Postgres instance, the exact
build flags, differences in generated asm code, etc.
I find it hard to beli
Hi
@imre : Thank you sharing the links on “ Phoronix has been tested the
PostgreSQL 13”.
I compared my test results with Phoronix test suit” . It has too
deviations(may be hardware environment and PostgreSQL version)
I think PostgreSQLv13 may have issues with Auto vacuum and currently I’m
using wi
> .. optimisation flags like O3
> And please suggest ... to check on the performance difference
The Phoronix has been tested the PostgreSQL 13 with Clang 12 + GCC 11.1 On
Xeon Ice Lake
* "The CFLAGS/CXXFLAGS set throughout testing were "-O3 -march=native
-flto" *
* as would be common for HPC sy
Hi
PostgreSQLv14 source code build with GCCv11.2 and Clangv12(without JIT)
with optimisation flags like O3 and tested with HammerDB
Observed TPC-H , GCC performance better than Clang(without JIT). The
performance difference ~22% and also noticed the assembly code difference
GCC vs Clang( e.g. GCC
