I have been using ifort version 22.214.171.1244 and just updated to OneAPI ifort version 2021.3.0
and ifx version 2021.3.0 Beta. Doing some speed test of my production code that uses openmp I find that ifort classic is running much faster than the ifx.
ifort 126.96.36.1994 and ifort 2021.3.0 run at exactly the same speed:
However, ifx runs at:
The compiler flags are -O3 -xHost -qopenmp for both runs. This is on dual cpu dell precision 7920 with Intel(R) Xeon(R) Gold 6256 CPU @ 3.60GHz. The library paths for both compilations point to the same place (is this correct?) in my makefiles. Am I doing something wrong or does the beta version have some debug features etc that is slowing the runs down. Thanks!
For this kind of comparison VTune profiler should have been used. The timing results as posted by you are too abstract to reveal the exact reason of apparent much worse performance of the code compiled by the 'ifx'.
Yes, naturally, but I found the following statement from Intel:
"ifort will remain Intel’s recommended production compiler until ifx has performance and features superior to ifort. In the future, when ifx functionality and performance equivalence or better against ifort is achieved, Intel may suggest using ifx, instead of, ifort for performance critical applications."
The critical words in the text you quoted are "until" and "In the future". At present, ifx is an early beta compiler whose performance is definitely NOT superior to ifort. Feel free to try ifx, but ifort remains the production compiler of choice for now.
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