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Subject: Re: [OMPI devel] [OMPI users] openmpi 1.4 broken -mca coll_tuned_use_dynamic_rules 1
From: Lenny Verkhovsky (lenny.verkhovsky_at_[hidden])
Date: 2009-12-30 09:57:50


The only workaround that I found is a file with dynamic rules.
This is an example that George sent me once. It helped for me, until it will
be fixed.

" Lenny,

You asked for dynamic rules but it looks like you didn't provide them.
Dynamic rules allow the user to specify which algorithm to be used for each
collective based on a set of rules. I corrected the current behavior, so it
will not crash. However, as you didn't provide dynamic rules, it will just
switch back to default behavior (i.e. ignore the
coll_tuned_use_dynamic_rules MCA parameter).

As an example, here is a set of dynamic rules. I added some comment to
clarify it, but if you have any questions please ask.

2 # num of collectives
3 # ID = 3 Alltoall collective (ID in coll_tuned.h)
1 # number of com sizes
64 # comm size 64
2 # number of msg sizes
0 3 0 0 # for message size 0, bruck 1, topo 0, 0 segmentation
8192 2 0 0 # 8k+, pairwise 2, no topo or segmentation
# end of collective rule
#
2 # ID = 2 Allreduce collective (ID in coll_tuned.h)
1 # number of com sizes
1 # comm size 2
2 # number of msg sizes
0 1 0 0 # for message size 0, basic linear 1, topo 0, 0 segmentation
1024 2 0 0 # for messages size > 1024, nonoverlapping 2, topo 0, 0
segmentation
# end of collective rule
#

And here is what I have in my $(HOME)/.openmpi/mca-params.conf to activate
them:
#
# Dealing with collective
#
coll_base_verbose = 0

coll_tuned_use_dynamic_rules = 1
coll_tuned_dynamic_rules_filename = **the name of the file where you saved
the rules **

"

On Wed, Dec 30, 2009 at 4:44 PM, Daniel Spångberg <daniels_at_[hidden]>wrote:

> Interesting. I found your issue before I sent my report, but I did not
> realise that this was the same problem. I see now that your example is
> really for openmpi 1.3.4++
>
> Do you know of a work around? I have not used a rule file before and seem
> to be unable to find the documentation for how to use one, unfortunately.
>
> Daniel
>
> Den 2009-12-30 15:17:17 skrev Lenny Verkhovsky <lenny.verkhovsky_at_[hidden]
> >:
>
>
> This is the a knowing issue,
>> https://svn.open-mpi.org/trac/ompi/ticket/2087
>> Maybe it's priority should be raised up.
>> Lenny.
>>
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