On 8/27/17 2:31 AM, Arkadi Sharshevsky wrote: >> Also, this dpipe capability seems to be just dumping data structures >> maintained by the driver. ie., you can compare the mlxsw view of >> networking state to IPv4 and IPv6 level tables. Any plans to offer a >> command that reads data from the h/w and passes that back to the user? >> i.e, a command to compare kernel tables to h/w state? >> > > So this infra should provide several things- > > 1) Reveal the interactions between various hardware tables > 2) Counters for this tables > 3) Debugabillity > > The first two can be achieved right now. Regarding debugabillity, which > is a bit vague, the current assumption is that the drivers internal data > structures are synced with hardware (which is no always true), and maybe > are not synced with the kernel, so this can be achieved right now by > dumping the internal state of the driver. Furthermore, the counters are > dumped from the hardware and give the user additional indication. > > I completely agree that the hardware should be dumped in order to > validate the internal data structures are really synced with HW. This > could be usable for observing data corruptions inside the ASIC and > various complex bugs. > > In order to address that I though about maybe add a flag called > "validate_hw" so that during the dump the driver<-->hw state could be > validated. > > What do you think about it?
It is not just a matter of dumping hardware state. The data returned by dump needs to be consistent across platforms and vendors. If the intent is validating hardware state matches kernel state (ie., h/w forwarding matches s/w forwarding), then the hardware state should be dumped by the driver in a form that parallels kernel state. e.g., dump h/w routes, neighbor entries, fdb's in a form and granularity similar to what is done for kernel tables. With the recent dpipe changes that allows kernel to driver cache and kernel to h/w state comparisons.
