diff options
| -rw-r--r-- | drivers/net/ethernet/microsoft/mana/gdma_main.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c index 3504507477c6..6c4e143972a1 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; |