On Tue, May 27, 2025 at 03:10:15PM -0400, Yury Norov wrote:
> So now git will think that you're the author of the patch.
>
> If author and sender are different people, the first line in commit
> message body should state that. In this case, it should be:
>
> From: Yury Norov <[email protected]>
>
> Please consider this one example
>
> https://patchew.org/linux/[email protected]/[email protected]/
>
> Thanks,
> Yury
>
Understood, Thank you Yury. I'll make this change in the next version
Regards,
Shradha.
> On Tue, May 27, 2025 at 08:58:25AM -0700, Shradha Gupta wrote:
> > Commit 91bfe210e196 ("net: mana: add a function to spread IRQs per CPUs")
> > added the irq_setup() function that distributes IRQs on CPUs according
> > to a tricky heuristic. The corresponding commit message explains the
> > heuristic.
> >
> > Duplicate it in the source code to make available for readers without
> > digging git in history. Also, add more detailed explanation about how
> > the heuristics is implemented.
> >
> > Signed-off-by: Yury Norov [NVIDIA] <[email protected]>
> > Signed-off-by: Shradha Gupta <[email protected]>
> > ---
> > .../net/ethernet/microsoft/mana/gdma_main.c | 41 +++++++++++++++++++
> > 1 file changed, 41 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> > b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> > index 4ffaf7588885..f9e8d4d1ba3a 100644
> > --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> > +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> > @@ -1288,6 +1288,47 @@ void mana_gd_free_res_map(struct gdma_resource *r)
> > r->size = 0;
> > }
> >
> > +/*
> > + * Spread on CPUs with the following heuristics:
> > + *
> > + * 1. No more than one IRQ per CPU, if possible;
> > + * 2. NUMA locality is the second priority;
> > + * 3. Sibling dislocality is the last priority.
> > + *
> > + * Let's consider this topology:
> > + *
> > + * Node 0 1
> > + * Core 0 1 2 3
> > + * CPU 0 1 2 3 4 5 6 7
> > + *
> > + * The most performant IRQ distribution based on the above topology
> > + * and heuristics may look like this:
> > + *
> > + * IRQ Nodes Cores CPUs
> > + * 0 1 0 0-1
> > + * 1 1 1 2-3
> > + * 2 1 0 0-1
> > + * 3 1 1 2-3
> > + * 4 2 2 4-5
> > + * 5 2 3 6-7
> > + * 6 2 2 4-5
> > + * 7 2 3 6-7
> > + *
> > + * The heuristics is implemented as follows.
> > + *
> > + * The outer for_each() loop resets the 'weight' to the actual number
> > + * of CPUs in the hop. Then inner for_each() loop decrements it by the
> > + * number of sibling groups (cores) while assigning first set of IRQs
> > + * to each group. IRQs 0 and 1 above are distributed this way.
> > + *
> > + * Now, because NUMA locality is more important, we should walk the
> > + * same set of siblings and assign 2nd set of IRQs (2 and 3), and it's
> > + * implemented by the medium while() loop. We do like this unless the
> > + * number of IRQs assigned on this hop will not become equal to number
> > + * of CPUs in the hop (weight == 0). Then we switch to the next hop and
> > + * do the same thing.
> > + */
> > +
> > static int irq_setup(unsigned int *irqs, unsigned int len, int node)
> > {
> > const struct cpumask *next, *prev = cpu_none_mask;
> > --
> > 2.34.1
