[Spread-users] Increasing the size of the group name

[Ryan Caudy]

Just a guess, but it seems likely from the way its used that as long as 
the increase to the private name size is a multiple of 4 bytes (for 32 
bit architectures), you shouldn't see bus errors.  That is, make sure 
the max private name is a multiple of 4, and the max group name as well, 
for which you have the formula you mentioned.  If this workaround 
doesn't work, let me know.

As far as I know, the reason for the two separate definitions is to hide 
the "real" formula from the user, and give a very simple set of headers 
to be used by clients programs linking with libspread.  I agree that it 
may need further consideration.

--Ryan

James J. Wagner wrote:

> No, I do need a larger group name. Changing the size of the MAX_PRIVATE_NAME
> changes the size of the MAX_GROUP_NAME because the MAX_GROUP_NAME is defined as
> 
> 	#define MAX_GROUP_NAME (1+MAX_PRIVATE_NAME+1+MAX_PROC_NAME)
> 
> At least it is defined as that in spread_params.h. It is hardcoded to 32 in
> sp.h, but I changed it to the above (so it would adjust).
> 
> Good to know you aren't having problems on linux. That gives me hope that once I
> got pass the bus error (by changing the size from 32 to 30) that things should
> work.
> 
> 	Thanks,
> 		James.
> 
> 
>>-----Original Message-----
>>From: Greg Shebert [mailto:gshebert at efs-us.com]
>>Sent: Friday, January 23, 2004 1:46 PM
>>To: James J. Wagner
>>Subject: Re: [Spread-users] Increasing the size of the group name
>>
>>
>>hey there
>>
>>i think what you are saying, first of all, is that you need a larger
>>private name, not a larger group name... this will make the
>>size of the
>>private group name larger but the group name stays the same
>>
>>i ran into the same problem and upped the private name to 32... on
>>solaris i started having bus errors all over the place...
>>
>>some of the daemon code is poorly written and makes some assumptions
>>about things being aligned on word boundarys... messing with
>>the private
>>name size changes the alignments and causes your bus errors...
>>
>>i've submitted the crash bugs and am hoping it will be fixed
>>in a later
>>version...
>>
>>other than the solaris crash bugs, i've been running on linux
>>with these
>>increased sizes with no problems
>>
>>-gre-g
>>
>>
>>On Fri, 2004-01-23 at 14:26, James J. Wagner wrote:
>>
>>>Running on Solaris.
>>>
>>>I need to increase the size of the group name. I have done so by
>>>increasing MAX_PRIVATE_NAME from 10 to 30. This *seems* to work (has
>>>worked so far in limited testing). A few comments though:
>>>
>>> 1) Increasing it to 32 causes a bus error
>>>
>>> 2) Increasing it to 30 works - so there is some set of
>>
>>magic numbers
>>
>>>that seem to work
>>>
>>> 3) I noticed this constant is defined in both sp.h and
>>>spread_params.h - why is this defined in two places?
>>>
>>> 4) While modifying these two files I noticed that sp.h defines
>>>MAX_GROUP_NAME to be 32, whereas spread_params.h defines it to be a
>>>formula. I updated sp.h so that it also uses a formula,
>>
>>thus adjusting
>>
>>>the value as I increase MAX_PRIVATE_NAME.
>>>
>>>A couple of questions:
>>>
>>>1) Are there any known issues associated with increasing the size of
>>>the group name?
>>>
>>>2) Is there a way to know what will work (30 vs 32, etc.)
>>
>>or if I need
>>
>>>to make it larger do I need to just use a trial and error approach?
>>>
>>>    Thanks,
>>>        James.
>>>
>>
> 
> 
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-- 
Ryan W. Caudy
Center for Networking and Distributed Systems
Department of Computer Science
Johns Hopkins University