Code is moving the completion queue doorbell after processing all completed
events and sending callbacks to the block layer on each iteration.
This is causing a performance drop when a lot of jobs are queued towards
the HW. Move the completion queue doorbell on each loop instead and allow new
jobs to be queued by the HW.
Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
drivers/nvme/host/pci.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index d10d2f2..33d9b5b 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -810,13 +810,12 @@ static void nvme_process_cq(struct nvme_queue *nvmeq)
while (nvme_read_cqe(nvmeq, &cqe)) {
nvme_handle_cqe(nvmeq, &cqe);
+ nvme_ring_cq_doorbell(nvmeq);
consumed++;
}
- if (consumed) {
- nvme_ring_cq_doorbell(nvmeq);
+ if (consumed)
nvmeq->cqe_seen = 1;
- }
}
Agree with Keith that this is definitely not the way to go, it
adds mmio operations in the hot path with very little gain (if
at all).
--
To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
