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Re: SIMDebian: Debian Partial Fork with Radical ISA Baseline




On 2019-02-09 03:25, Mo Zhou wrote:
Hi folks,

For most programs the "-march=native" option is not expected to bring any significant performance improvement. However for some scientific applications this proposition doesn't hold. When I was creating the tensorflow debian package, I observed a significant performance gap between generic code and
kabylake (Intel 7XXX Series) code[1].

...

Generally speaking, in order to bump the ISA baseline for a given package, one could add the -march=xxx flag to {C,CXX,F}FLAGS by modifying debian/rules. However SIMDebian employes a more economic approach to this end: forking dpkg[5] and injecting -march=xxx flag to the system default flag list. With the resulting dpkg package, most debian packages could be rebuilt with bumped ISA
baseline without any code modification.



I think it would be more constructive to provide arch-specific packages for eigen/blas etc on amd64 which Conflict/Replace/Provide the standard packages.

That way a local administrator can choose to install them if they help improve performance.

Hacking dpkg itself for this purpose and forking an entire linux distribution is way too invasive and distracts from solving the actual problem.

Drew