[Ofvwg] OFV meeting notes - 7/21/15

[Liran Liss]

General approaches for addressing Verbs error codes were discussed.

While the Verbs error codes were not specified to date, the current MAN pages do indicate that errno values are used (either in the return value, or by inspecting errno).
Thus, it seems that we should continue to support errno, but with well-defined values.

Where more detailed errors are required, the API should be extended to provide additional information.
For example, adding an ibv_get_last_error() API, which would return detailed Verb error codes.

The first release of compliant code should ideally include both libibverbs and providers.
Specifically, consistent errno values should be returned for the same errors.
Providers that do not do all checks may add them at a later time, while adhering to the specified error codes.

Compliancy to the specified error codes should be indicated by a new capability, such as "Extended error reporting".
Applications can check this capability to know whether they can rely on the semantics of a given error code.

Error checking is used both for development productivity and efficiency.
These goals might contradict, as productivity requires detailed error checking and validation, while data-path operations should be efficient as possible.
As an optimization, an additional modifier could be added while opening a device to request an "-unsafe" device handle, which would return function pointers with minimal error checks. However:

-          The default shall support all standard errors

-          All errors that are detected in the unsafe mode should return standard codes

--Liran
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