Re: [ofw] ib-diags: compatability issue with ibstat

From: Hal Rosenstock <hal.rosenstock-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: "Hefty, Sean" <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: "Ira Weiny (weiny2-i2BcT+NCU+M@public.gmane.org)"
	<weiny2-i2BcT+NCU+M@public.gmane.org>,
	"linux-rdma
	(linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org)"
	<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"ofw-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org"
	<ofw-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org>
Subject: Re: [ofw] ib-diags: compatability issue with ibstat
Date: Fri, 23 Sep 2011 09:45:39 -0400	[thread overview]
Message-ID: <CAKzyTszJ8qbPMYgMFhAzkJVnGmgetggSU7BYN+1RxrVB3tBYqA@mail.gmail.com> (raw)
In-Reply-To: <CAKzyTsyH0rop69rTGUW_+kgfohyN-XiCLV4JsO9NLzyH9KpQAA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Fri, Sep 23, 2011 at 9:28 AM, Hal Rosenstock
<hal.rosenstock-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Wed, Sep 21, 2011 at 3:06 PM, Hefty, Sean <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> wrote:
>> commit 1344cb3feacafc462440dabfa5997c5205486d83 added support for FDR10 in a way that is not compatible with Windows support.  Windows does not use files to read attribute information.
>>
>> I will probably need to obtain the necessary information using ibverbs on windows by reading port attributes.  I don't think FDR10 support is available through ibverbs on linux yet, but would this be acceptable?  Is there some other way that you'd like to handle this?  The other option I can think of is moving is_fdr10() and sys_read_string() out of ibstat.c and into a linux specific file, so that windows can provide its own implementation.  Thoughts?
>
> I think there are 2 (related but somewhat separate) issues here:
> 1. How to obtain is_fdr10
> 2. Whether ibverbs should be used for this (in windows, linux, both)
>
> The only way to determine whether fdr10 is active or not is via the
> vendor proprietary MAD. That info may be reflected in some other API
> (and/or file) so that MAD does not need to be reissued. In a separate
> thread on linux-rdma, there was discussion on a couple of different
> ways to do that from verbs and in this thread that there's no sysfs
> equivalent in Windows. You've already stated that the Windows support
> is using libibverbs for libibumad support so it seems appropriate to
> me to do the same here (in Windows at least).

The proper place for is_fdr10 is in libibumad (and then we wouldn't be
discussing libibverbs w/ibstat) but that was not done to avoid a
change to the umad port structure.

-- Hal

>
> -- Hal
>
>>
>> - Sean
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>
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