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dmaengine: idxd: assign MSIX vectors to each WQ rather than roundrobin

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IOPS increased when changing MSIX vector to per WQ from roundrobin.
Allows descriptor to be completed by the submitter improves caching
locality.

Suggested-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Link: https://lore.kernel.org/r/162456717326.1130457.15258077196523268356.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Dave Jiang 2021-06-24 13:39:33 -07:00 committed by Vinod Koul
parent ac24a2dc06
commit 6cfd9e62e3
2 changed files with 8 additions and 30 deletions
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2
drivers/dma/idxd/idxd.h
View file

@ -153,7 +153,6 @@ struct idxd_wq {
enum idxd_wq_state state;
unsigned long flags;
union wqcfg *wqcfg;
u32 vec_ptr; /* interrupt steering */
struct dsa_hw_desc **hw_descs;
int num_descs;
union {
@ -290,7 +289,6 @@ struct idxd_desc {
struct list_head list;
int id;
int cpu;
unsigned int vector;
struct idxd_wq *wq;
};

36
drivers/dma/idxd/submit.c
View file

@ -22,22 +22,13 @@ static struct idxd_desc *__get_desc(struct idxd_wq *wq, int idx, int cpu)
desc->hw->pasid = idxd->pasid;
/*
* Descriptor completion vectors are 1...N for MSIX. We will round
* robin through the N vectors.
* On host, MSIX vecotr 0 is used for misc interrupt. Therefore when we match
* vector 1:1 to the WQ id, we need to add 1
*/
wq->vec_ptr = (wq->vec_ptr % idxd->num_wq_irqs) + 1;
if (!idxd->int_handles) {
desc->hw->int_handle = wq->vec_ptr;
} else {
desc->vector = wq->vec_ptr;
/*
* int_handles are only for descriptor completion. However for device
* MSIX enumeration, vec 0 is used for misc interrupts. Therefore even
* though we are rotating through 1...N for descriptor interrupts, we
* need to acqurie the int_handles from 0..N-1.
*/
desc->hw->int_handle = idxd->int_handles[desc->vector - 1];
}
if (!idxd->int_handles)
desc->hw->int_handle = wq->id + 1;
else
desc->hw->int_handle = idxd->int_handles[wq->id];
return desc;
}
@ -130,19 +121,8 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
* Pending the descriptor to the lockless list for the irq_entry
* that we designated the descriptor to.
*/
if (desc->hw->flags & IDXD_OP_FLAG_RCI) {
int vec;
/*
* If the driver is on host kernel, it would be the value
* assigned to interrupt handle, which is index for MSIX
* vector. If it's guest then can't use the int_handle since
* that is the index to IMS for the entire device. The guest
* device local index will be used.
*/
vec = !idxd->int_handles ? desc->hw->int_handle : desc->vector;
llist_add(&desc->llnode, &idxd->irq_entries[vec].pending_llist);
}
if (desc->hw->flags & IDXD_OP_FLAG_RCI)
llist_add(&desc->llnode, &idxd->irq_entries[wq->id + 1].pending_llist);
return 0;
}