[openib-general] Advice

[Scott A. Friedman]

Hal Rosenstock wrote:
> On Thu, 2006-01-19 at 23:55, Scott A. Friedman wrote:
>> Sean Hefty wrote:
>>>> 1. What usermode tools should I use if I want to use the modules that
>>>> are part of the current kernels (e.g. Fedora). The OpenIB subversion
>>>> code, the IBGD stuff or something else.
>>> Not sure what IBGD is.  The OpenIB svn code matches with that shipping in the
>>> current kernels.
>>>
>> Sorry, I mean the Mellanox Gold distribution thing. Using this is kinda 
>> a problem for me since I need to use a recent kernel - to support some 
>> non Infiniband stuff.
> 
> You don't necessarily need to use IBGD. There is overlap. It depends on
> what you need/use out of this. Mellanox is working on an IB Gold 2 based
> on OpenIB too.
>

I will keep an eye out for it. However, they tend to only support 
particular kernel versions which doesn't work for us.

>> Just so I understand. When you say 'svn code matches' it means a) the 
>> kernel modules are the same (or close enough). b) the usermode stuff 
>> will/should work without a problem. Could you be a little more specific? 
>> Just curious how this works until things stabilize more.
> 
> I think Sean meant (correct me if I'm wrong here) svn code that matches
> the kernel in use (2.6.x) at a certain version (e.g. say 4507 for
> 2.6.9). This includes both kernel and userspace changes to the same
> OpenIB svn version. These are periodically updated but lag the head of
> the tree for obvious reasons.
> 

Got it - thanks.

>>>> 2. Is there any reason to *not* use the kernel modules that are now
>>>> included with the kernel.org or Fedora kernels? If so, which to use?
>>> Several modules in svn are not yet available in the kernel, so it depends on
>>> what you are trying to do.
>>>
>> Mainly, I am interested in the verb layer for know so my needs are not 
>> that great. However, is there a reason to compile and use the svn kernel 
>> modules in place of the supplied ones? Or, as you mentioned above - are 
>> fixes/patches picked up by the distributions in between stable kernel 
>> releases.
> 
> Just the verbs ? I think the answer depends on what you are specifically
> using in the verbs. It has not been released as 1.0 yet but close.
> Roland is best to comment on this.
> 

Well, we are porting some code written for VI and the verbs seem to be 
the most direct way of getting things going. I suppose later moving to a 
higher level would make sense (uDAPL?)

>>>> 3. How stable is the subversion code? Is it just for testers?
>>> In general, the tip of svn gen2/trunk is stable.  Bugs are usually fixed within
>>> a relatively short time (couple of hours to a day).  The drawback is that it
>>> targets the latest kernel release; however, backport patches are available.
>>>
>> Hmm, this is what I am looking for so that is actually a good thing for 
>> me. Except for having to rebuild the kernel to use the svn driver code. 
>> I suppose that I could just stick with building the usermode stuff and 
>> use the supplied kernel modules since I am not using any of the missing 
>> stuff.
> 
> Not always.. Sometimes there are related kernel changes.
> 
>> I also noticed that a person from redhat has provided some rpm modules 
>> of the usermode libraries. Is anyone using these? Is this a reasonable 
>> way to go? I suppose it is just a convenience.
> 
> Some people are using and testing these packages.
> 
> -- Hal
> 
>> Thanks again,
>> Scott
>>

Sounds like just building the svn code is the easiest.

Thanks for all your comments.
Scott