Re: [PATCH v2] opensm: Modify connect_roots to allow connectivity between all switches

["Eli Dorfman (Voltaire)" <dorfman.eli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Yevgeny Kliteynik wrote:
> Eli,
> 
> On 13-Jun-10 6:10 PM, Eli Dorfman (Voltaire) wrote:
>> After a second thought and in order not to break current configuration,
>> I send this modified patch that does not change connect_roots option but
>> changes its functionality in up-down (I think that in fat-tree it is
>> already implemented)
>>
>> Modify connect_roots option to allow connectivity between
>> all switches in up-down routing algorithm and in this way be
>> fully IBA compliant
>>
>> Signed-off-by: Eli Dorfman<elid-smomgflXvOZWk0Htik3J/w@public.gmane.org>
>> ---
>>   opensm/man/opensm.8.in         |    2 +-
>>   opensm/opensm/main.c           |    2 +-
>>   opensm/opensm/osm_ucast_updn.c |    4 +---
>>   3 files changed, 3 insertions(+), 5 deletions(-)
>>
>> diff --git a/opensm/man/opensm.8.in b/opensm/man/opensm.8.in
>> index 9053611..c67126e 100644
>> --- a/opensm/man/opensm.8.in
>> +++ b/opensm/man/opensm.8.in
>> @@ -174,7 +174,7 @@ the host comes back online.
>>   .TP
>>   \fB\-z\fR, \fB\-\-connect_roots\fR
>>   This option enforces routing engines (up/down and
>> -fat-tree) to make connectivity between root switches and in
>> +fat-tree) to make connectivity between all switches and in
>>   this way to be fully IBA complaint. In many cases this can
>>   violate "pure" deadlock free algorithm, so use it carefully.
>>   .TP
>> diff --git a/opensm/opensm/main.c b/opensm/opensm/main.c
>> index 0093aa7..82ca78f 100644
>> --- a/opensm/opensm/main.c
>> +++ b/opensm/opensm/main.c
>> @@ -187,7 +187,7 @@ static void show_usage(void)
>>              "          Sets the SL to use to communicate with the
>> SM/SA. Defaults to 0.\n\n");
>>       printf("--connect_roots, -z\n"
>>              "          This option enforces routing engines (up/down
>> and \n"
>> -           "          fat-tree) to make connectivity between root
>> switches\n"
>> +           "          fat-tree) to make connectivity between all
>> switches\n"
>>              "          and in this way be IBA compliant. In many
>> cases,\n"
>>              "          this can violate \"pure\" deadlock free
>> algorithm, so\n"
>>              "          use it carefully.\n\n");
>> diff --git a/opensm/opensm/osm_ucast_updn.c
>> b/opensm/opensm/osm_ucast_updn.c
>> index 164c6f4..f44ca24 100644
>> --- a/opensm/opensm/osm_ucast_updn.c
>> +++ b/opensm/opensm/osm_ucast_updn.c
>> @@ -314,9 +314,7 @@ static int updn_set_min_hop_table(IN updn_t * p_updn)
>>            item = cl_qmap_next(item)) {
>>           p_sw = (osm_switch_t *)item;
>>           /* Clear Min Hop Table */
>> -        if (p_subn->opt.connect_roots)
>> -            updn_clear_non_root_hops(p_updn, p_sw);
>> -        else
>> +        if (!p_subn->opt.connect_roots)
>>               osm_switch_clear_hops(p_sw);
>>       }
>>
> 
> What kind of testing was done for this?
> I have a strong feeling that it will break up/down.
> If the connect_roots option is on, you will not clear
> the lid matrix at all, and it will contain also the
> down/up routes.

that is the idea.
instead of leaving only up/dpwn routes we want to keep routes between all switches.
the routes between host nodes will still be up/down.

Eli

> 
> -- Yevgeny

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