On 9/22/2021 10:45 AM, Christoph Hellwig wrote:

On Wed, Sep 22, 2021 at 10:44:20AM +0300, Max Gurtovoy wrote:

quoted

So for now, as mentioned, till we have some ib_ API, lets set it to 128.

Please just add the proper ib_ API, it should not be a whole lot of
work as we already do that calculation anyway for the R/W API setup.

We don't do this exact calculation since only the low level driver knows 
that number of WQEs we need for some sophisticated WR.

The API we need is like ib_get_qp_limits when one provides some input on 
the operations it will issue and will receive an output for it.

Then we need to divide it by some factor that will reflect the amount of 
max WRs per NVMe request (e.g mem_reg + mem_invalidation + rdma_op + 
pi_yes_no).

I spoke with Jason on that and we decided that it's not a trivial patch.

is it necessary for this submission or can we live with 128 depth for 
now ? with and without new ib_ API the queue depth will be in these sizes.

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