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Re: (Problems with) coexistence of target and offloading compiler installations


On Fri, Jun 10, 2016 at 11:31:33 +0200, Jakub Jelinek wrote:
> On Fri, Jun 10, 2016 at 09:39:02AM +0200, Thomas Schwinge wrote:
> > But I'm actually confused as to seeing libgomp.so in that list -- given
> > the conflict of which compiler installations' libgomp.so "wins", I wonder
> > how it can be working that some of the functions in there are supposed to
> > behave differently on/are compiled differently for target vs. offloading
> > target?  Or did I do/understand something wrong?  For a lot of other
> 
> For intelmic offloading, I believe all the libraries should be the same
> (unless one chooses e.g. different tuning or ISA in between the two compiler
> installations), including libgomp, so one should be able to just use the
> libraries from the primary compiler.  At least that has been the goal,
> omp_is_initial_device should be handled by overriding the symbol in the
> magic executable.

Right, currently there is no difference between host and mic libraries in gcc.

> For emul certainly, for XeonPhi KNL PCIe HW, I haven't had a possibility to see
> it in action yet, so I don't know how exactly is the filesystem typically
> handled, if the offloading device has e.g. NFS mount of the host's
> filesystem, or if all the libraries are always copied over on demand over
> the bus, whatever.

Some libraries are copied during the boot of the card (e.g. libc.so), others are
copied during the first offload from the app (e.g. libgomp.so).

  -- Ilya


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