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Subject: Re: [OMPI devel] FDR: bad patch? (was: 1.6rc3 is out)
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2012-05-09 12:26:33


On May 9, 2012, at 11:33 AM, <Ludovic.Hablot_at_[hidden]> wrote:

> Well, looking at the libverbs sources, it seems that there is a patch for devinfo (cf below).
>
> Thus, the correct speeds, according to the libibverbs patch. And, if I understand well, they must be
> multiplied by the coding ratio to get the real link speed.
>
> I joined another patch. I don't know if we should remove the case 4 and fall through case 8 or just keep it as I do.

Your patch looks good to me... but what do I know? :-)

Mellanox: please comment.

> Regards,
>
> Ludovic
>
> libibverbs/fixes/add_support_for_extended_speends.patch
>
> [PATCH]libibverbs: Add support for extended speeds
>
> 8: FDR-10 is a proprietary link speed which is 10.3125 Gbps at 64/66
> encoding rather than 8b10b encoding.
> 16: FDR - 14.0625 Gbps
> 32: EDR - 25.78125 Gbps
>
> +--- a/examples/devinfo.c
> ++++ b/examples/devinfo.c
> +@@ -139,7 +139,12 @@ static const char *speed_str(uint8_t speed)
> + switch (speed) {
> + case 1: return "2.5 Gbps";
> + case 2: return "5.0 Gbps";
> +- case 4: return "10.0 Gbps";
> ++
> ++ case 4: /* fall through */
> ++ case 8: return "10.0 Gbps";
> ++
> ++ case 16: return "14.0 Gbps";
> ++ case 32: return "25.0 Gbps";
> + default: return "invalid speed";
> + }
> + }
>
>
>
> -----devel-bounces_at_[hidden] a écrit : -----
> A : devel_at_[hidden]
> De : Peter Kjellström
> Envoyé par : devel-bounces_at_[hidden]
> Date : 09/05/2012 16:35
> Objet : Re: [OMPI devel] FDR: bad patch? (was: 1.6rc3 is out)
>
> On Wednesday 09 May 2012 10.20.47 Jeff Squyres wrote:
> ...
> > I don't have any QDR or FDR equipment -- what's the typical active_width for
> > QDR and FDR?
> >
> > QDR is 32000, so is that active_speed of 4 and active_width of 4? (8000 * 4
> > = 32000)?
> >
> > FDR is 56000 (right?
>
> Pretty much all IB is 4x to host.
>
> 4x QDR is 40 Gbps at link level => 8 Gbps data per link (8/10 coding)
> 4x FDR10 is 40 Gbps at link level => ~9.7 Gbps data per link (64/66 coding)
> 4x FDR is 56 Gbps at link level => ~13.5 Gbps data per link (64/66 coding)
>
> /Peter
>
> > I haven't kept up with IB specs since Cisco killed
> > IB...), so what are its active_speed and active_width values?
>
> --
> -= Peter Kjellström
> -= National Supercomputer Centre
> _______________________________________________
> devel mailing list
> devel_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>
>
> [pièce jointe "signature.asc" supprimée par Ludovic Hablot/EXT/FR/BULL]
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-- 
Jeff Squyres
jsquyres_at_[hidden]
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