From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bart.VanAssche@wdc.com (Bart Van Assche)
Date: Tue, 14 Nov 2017 16:28:07 +0000
Subject: [PATCH v3 1/9] RDMA/core: Add implicit per-device completion
 queue pools
In-Reply-To: <20171108095742.25365-2-sagi@grimberg.me>
References: <20171108095742.25365-1-sagi@grimberg.me>
 <20171108095742.25365-2-sagi@grimberg.me>
Message-ID: <1510676885.2280.9.camel@wdc.com>

On Wed, 2017-11-08@11:57 +0200, Sagi Grimberg wrote:
> +struct ib_cq *ib_find_get_cq(struct ib_device *dev, unsigned int nr_cqe,
> +               enum ib_poll_context poll_ctx, int affinity_hint)
> +{
> +       struct ib_cq *cq, *found;
> +       unsigned long flags;
> +       int vector, ret;
> +
> +       if (poll_ctx >= ARRAY_SIZE(dev->cq_pools))
> +               return ERR_PTR(-EINVAL);
> +
> +       if (!ib_find_vector_affinity(dev, affinity_hint, &vector)) {
> +               /*
> +                * Couldn't find matching vector affinity so project
> +                * the affinty to the device completion vector range
> +                */
> +               vector = affinity_hint % dev->num_comp_vectors;
> +       }

So depending on whether or not the HCA driver implements .get_vector_affinity()
either pci_irq_get_affinity() is used or "vector = affinity_hint %
dev->num_comp_vectors"? Sorry but I think that kind of differences makes it
unnecessarily hard for ULP maintainers to provide predictable performance and
consistent behavior across HCAs.

Bart.