Re: [PATCH 2/3] qla2xxx: SAN congestion management(SCM) implementation.

[James Smart <james.smart@broadcom.com>]

On 6/11/2020 10:42 AM, Shyam Sundar wrote:
> Seems like this (and a previous email) never made it to the reflector, resending.
>
> The suggestions make sense to me, and I have made most of the recommended changes.
> I was looking for some guidance on placements of the sim stats structures.
>
>> On May 29, 2020, at 11:53 AM, Shyam Sundar <ssundar@marvell.com> wrote:
>>
>> James,
>>       I was thinking of adding a structures for tracking the target FPIN stats.
>>
>> struct fc_rport_statistics {
>> uint32_t link_failure_count;
>> uint32_t loss_of_sync_count;
>> ....
>> }
>>
>> under fc_rport:
>>
>> struct fc_rport {
>>
>> /* Private (Transport-managed) Attributes */
>> struct fc_rport_statistics;
>>
>>       For host FPIN stats (essentially the alarm & warning), was not sure if I should add them to the fc_host_statistics or
>> define a new structure under the Private Attributes section within the fc_host_attrs/fc_vport.

my initial thought was the same

>>
>>       In theory, given that the host stats could be updated both via signals and FPIN, one could argue that it would make sense
>> to maintain it with the current host statistics, but keeping it confined to transport will ensure we have a uniform way of handling
>> congestion and peer congestion events.

but then I have the same thoughts as well. And the commonization of the 
parsing and incrementing makes a lot more sense.

>>
>>      Would appreciate your thoughts there.
>>
>> Thanks
>> Shyam
>>     
>>


I would put them under the Dynamic attributes area in fc_host_attrs and 
fc_rport.
fc_host_attrs:
fpin_cn              incremented for each Congestion Notify FPIN
cn_sig_warn     incremented for each congestion warning signal
cn_sig_alarm    incremented for each congestion alarm signal
fpin_dn             incremented for each Delivery Notification FPIN 
where attached wwpn is local port
fpin_li                incremented for each Link Integrity FPIN where 
attached wwpn is local port

fc_rport:
fpin_dn             incremented for each Delivery Notification FPIN 
where attached wwpn is the rport
fpin_li               incremented for each Link Integrity FPIN where 
attached wwpn is the rport
fpin_pcn           incremented for each Peer Congestion Notify FPIN 
where attached wwpn is the rport

For the cn_sig_xxx values, the driver would just increment them.
For the fpin_xxx values - we'll augment the fc_host_fpin_rcv routine to 
parse the fpin and increment the fc_host or fc_rport counter.

-- james