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Re: [HTCondor-users] check for cpu instruction?
Good explanation, Tom - one could envision a submit tool that checks for vector instructions in an executable and generates a rank expression to prefer the highest compatible instruction set and require the minimum. That is, assuming the executable isn't a wrapper script.
From: HTCondor-users [mailto:htcondor-users-bounces@xxxxxxxxxxx] On Behalf Of Thomas Patrick Downes
Sent: Thursday, May 17, 2018 12:07 PM
To: HTCondor-Users Mail List <htcondor-users@xxxxxxxxxxx>
Subject: [External] Re: [HTCondor-users] check for cpu instruction?
What Greg means is that it is impossible for HTCondor to determine (with 100% certainty) which set of instructions will be executed in a binary given a set of input data. The more general problem is called the halting problem because the question is posed at "will the program exit?" but you can also re-pose the question as "will the program reach this particular instruction?"
It is not uncommon for compilers / authors to build binaries that detect the instruction set environment at runtime and execute different instructions on different platforms. So the mere presence of an AVX512 instruction inside a binary does not, in fact, mean it won't run on a system without AVX512.