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Subject: Re: [hwloc-devel] towards PLPA-like API in 1.0
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2009-11-12 13:05:32


On Nov 12, 2009, at 9:56 AM, Brice Goglin wrote:

> Well, the list of good ideas will be very short then :) Most remaining
> functions are about manipulating core and socket ids, we don't need
> that
> at all in hwloc anymore.
>
> My feeling is that converting an application from PLPA's
> core_id/socket_id API into the hwloc API will be non-trivial. So at
> least the current hwloc_plpa_* functions will be document a bit how to
> switch to the hwloc API.
>

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.

It may be useful to have the API be extensible; one thing I have heard
rumors about coming in the not-distant future is the concept of
"boards" (multiple motherboards in a single box). I.e., socket IDs
may be repeated; they are differentiated by board number.

-- 
Jeff Squyres
jsquyres_at_[hidden]