> .. 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 systems when building performance sensitive code."* *and the results:* https://www.phoronix.com/scan.php?page=article&item=clang12-gcc11-icelake&num=4 ( see ~ bottom of the page ) only the Postgres ( GCC 11 vs. LLVM Clang 12 Benchmarks On Xeon Ice Lake ) https://openbenchmarking.org/result/2105299-IB-COMPILERT91&sgm=1&ppt=D&sor&sgm=1&ppt=D&oss=Postgresql maybe you can replicate the Phoronix results ( but this is only gcc11.1 ! ) "Compare your own system(s) to this result file with the Phoronix Test Suite by running the command: phoronix-test-suite benchmark 2105299-IB-COMPILERT91" Regards. Imre arjun shetty <arjunshetty...@gmail.com> ezt írta (időpont: 2021. nov. 2., K, 18:13): > 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 inlined functionality compared to Clang). > > Environment details: > ————————- > OS :RHEL8.4 > Bare metal : Apple/AMD EPYC/IBM > Test(TPC-H) Benchmark Environment:HammerDB > > Is the performance difference mainly because of below points ? > 1 data over flow and calculations like int128(int128.c) and C arithmetic > operations(functions include in float.h e.g float4_mul) > > And please suggest is any another functionality or code points need to > check on the performance difference >
