7 ms·
That's definitely possible (it probably checks that the manufacturer ID is GenuineIntel), but nobody wants to distribute patched MKL versions, because it most l
by danieldk 6y ago
That's definitely possible (it probably checks that the manufacturer ID is GenuineIntel), but nobody wants to distribute patched MKL versions, because it most likely violates the MKL license.
It may even be easier to replace the function altogether with LD_PRELOAD.
- danieldk 6y agoIndeed works. A simple trace reveals that the function is called mkl_serv_intel_cpu_true(). Make a file with the following content: int mkl_serv_intel_cpu_true() { return 1; } Compile gcc -shared -o libfake.so fake.c Run LD_PRELOAD=libfake.so yourprogram And it uses the optimized AVX codepaths. Disclaimer: may not be legal in your country. I take no responsibility.
- ashleyn 6y agoWow. I wasn't quite expecting something as simple as "if CPU is not intel, make everything worse."
- colejohnson66 6y agoI’m sure their justification is that (1) they have no obligation to help AMD, and (2) how could you guarantee AMD implements CPUID the same as Intel (as in: what if AMD implements a feature bit differently?) Of course, the second one makes no sense as x86 programs run just as fine on AMD as Intel with the same feature set (albeit at different speeds)
- danieldk 6y agoBy the way, if you want make this permanent in a binary, there is no need to set LD_PRELOAD all the time. You could just add a DT_NEEDED entry to the dynamic section. E.g. something like: patchelf --add-needed libfakeintel.so yourbinary
- krageon 6y agoYou distribute a binary patch for a given MKL release, have your package download the official MKL release and then patch it using the binary patch. Nobody suffers, everyone wins.
- rasz 6y agoNo need to patch MKL, just your own binaries post compile.