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Subject: Re: [hwloc-devel] towards PLPA-like API in 1.0
From: Brice Goglin (Brice.Goglin_at_[hidden])
Date: 2009-11-23 13:25:10

Jeff Squyres wrote:
> FWIW, having a "simple" API like that might be a Good Thing...?
> I.e., just be able to bind to a specific thread/core/socket with a
> minimum fuss/muss. Even if such an API would be mainly syntactic sugar
> for other hwloc functionality -- there definitely is something to be
> said for "make the simple things simple". It will definitely (IMNSHO)
> extend hwloc's reach into a larger class of applications. Meaning:
> there are a variety of hard-coded apps out there that we'll never see;
> apps that run on specific servers for specific purposes, where the
> developers hard code in there "bind to cores 1-4" or "bind to sockets
> 1,3" because they already know the setup and this app is not intended
> to be portable.

I am looking at what we could add to the main API/helpers, here's what
could be useful:
* get_obj_under_by_type(topology, type, index, subtype, subindex)
returns for instance core 2 under socket 3. It's very easy
* Some people might want _under_under with 3 types/indexes. Not sure we
want it, or want to make it generic with arrays of types/indexes...
* Generic conversion routines between os_index and logical_index, like
get_obj_by_os_index(type, os_index) and get_os_index_by_type(type, index)
* Some kind of processor flag which tells us whether a physical proc
exists and is online