Dear mailing list, just out of curiosity has anyone any experience running Wien2k on a AVX512 capable machine (eg. the KNL accelerators or recent Intel skylake-avx512 CPUs)?
Recently my cluster updated to this skylake-avx512 machines however I'm unable to get any better performance for Wien2k. In particular MKL seem to suck, for example in single core performance (with the serial test_case) the eigenvalue problem is actually faster when I forbid the usage of AVX512 instructions: running with MKL_VERBOSE=1 MKL_ENABLE_INSTRUCTIONS=AVX2 MKL_VERBOSE ZHETRD(L,3481,0x2b74d8567cc0,3481,0x2b74d82121c0,0x2b74d8218e88,0x2b74e f769b00,0x2b74ef777490,452530,0) 10.21s CNR:OFF Dyn:1 FastMM:1 TID:0 NThr:1 with MKL_ENABLE_INSTRUCTIONS=AVX512 MKL_VERBOSE ZHETRD(L,3481,0x2b5397c96cc0,3481,0x2b53979411c0,0x2b5397947e88,0x2b53a ee98b00,0x2b53aeea6490,452530,0) 12.31s CNR:OFF Dyn:1 FastMM:1 TID:0 NThr:1 This is somewhat compensated by speedups in the hamilt part (the VML stuff and various ?GEMMs seem to be actually slightly faster), but overall the performance is mostly the same with and without the AVX512 stuff. OpenBLAS is maybe 15% slower so not an option as well... Moreover for MPI version I'm not able to get a correctly working ELPA compiled with the AVX512 support (I went for the latest elpa- 2018.11.001 version), it just returns bogus results and diverges after few iterations. If someone has this working I'd be really grateful for a working configure line, and advice with which elpa and which compiler version this was. Unfortunately I was not able to get any support from the cluster admins beyond "We see a 30% per-core performance increase in average" therefore asking here if anyone has experience with such machines. Any advice would be appreciated. Best regards Pavel _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html