Hi James,

On 02/28/2017 12:28 AM, James Smart wrote:
> I'd like to announce the availability of the Broadcom (Emulex) FC Target
> driver - efct.
> This driver has been part of the Emulex OneCore Storage SDK tool kit for
> Emulex
> SLI-4 adapters. The SLI-4 adapters support 16Gb/s and higher adapters.
> Although this
> kit has supported FCoE in the past, it is currently limited to FC support.
> 
> This driver provides the following:
> - Target mode operation:
>   - Functional with LIO-based interfaces
>   - Extensive use of hw offloads such as auto-xfer_rdy, auto-rsp, cmd
> cpu spreading
>   - High login mode - thousands of logins
>   - T-10 DIF/PI support  (inline and separate)
>   - NPIV support
> - Concurrent Initiator support if needed
> - Discovery engine has F_Port and fabric services emulation.
> - Extended mgmt interfaces:
>   - firmware dump api, including dump to host memory for faster dumps
>   - Healthcheck operations and watchdogs
> - Extended driver behaviors such as:
>   - polled mode operation
>   - multi-queue: cpu, roundrobin, or priority  (but not tied  to scsi-mq)
>   - long chained sgl's
>   - extensive internal logging and statistics
>   - Tuning parameters on modes and resource allocation to different
> features
> 
Yay! Finally!

> Broadcom is looking to upstream this driver and would like review and
> feedback.
> The driver may be found at the following git repository:
>     g...@gitlab.com:jsmart/efct-Emulex_FC_Target.git
> 
> 
> Some of the key questions we have are with lpfc :
> 1) Coexistence vs integration
> Currently, the efct driver maps to a different set of PCI ids than lpfc.
> It's very clear there's an overlap with lpfc, both on SLI-4 hw as well
> as initiator support.
> Although target mode support can be simplistically added to lpfc, what
> we've found is that doing so means a lot of tradeoffs. Some of the
> target mode features, when enabled,
> impact the initiator support and how it would operate.
> 
Can you clarify these?
Are these 'just' resource allocation problems or something else, too?

> 2) SLI-3 support
> lpfc provides SLI-3 support so that all FC adapters are supported,
> including the older ones.
> The form of the driver, based on its history, is SLI-3 with SLI-3
> adapted to SLI-4 at the point
> it hits the hardware. efct does not support SLI-3.
> 
I personally wouldn't have a problem with _not_ enabling SLI-3; after
all, this is (conceptually :-) new code, so we do not _need_ to support
older HW here.

> 3) complexity of configuration knobs caused by the kitchen-sink of
> features in lpfc ?
> we are pushing the limit on needing per-instance attributes rather than
> global module
> parameters.
> 
Yes, this is always a good idea. Also one might want to look at which of
those knobs are there for pure historical reasons, maybe we can cut down
on the number of knobs already :-)

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                   zSeries & Storage
h...@suse.de                          +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)

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