Trivial to do now, just need our own io_comp_batch on the stack and pass
that in to the usual command completion handling.
I pondered making this dependent on how many entries we had to process,
but even for a single entry there's no discernable difference in
performance or latency. Running a sync workload over io_uring:
t/io_uring -b512 -d1 -s1 -c1 -p0 -F1 -B1 -n2 /dev/nvme1n1 /dev/nvme2n1
yields the below performance before the patch:
IOPS=254820, BW=124MiB/s, IOS/call=1/1, inflight=(1 1)
IOPS=251174, BW=122MiB/s, IOS/call=1/1, inflight=(1 1)
IOPS=250806, BW=122MiB/s, IOS/call=1/1, inflight=(1 1)
and the following after:
IOPS=255972, BW=124MiB/s, IOS/call=1/1, inflight=(1 1)
IOPS=251920, BW=123MiB/s, IOS/call=1/1, inflight=(1 1)
IOPS=251794, BW=122MiB/s, IOS/call=1/1, inflight=(1 1)
which definitely isn't slower, about the same if you factor in a bit of
variance. For peak performance workloads, benchmarking shows a 2%
improvement.
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
drivers/nvme/host/pci.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index e916d5e167c1..fdb0716614c9 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1075,7 +1075,13 @@ static inline int nvme_poll_cq(struct nvme_queue *nvmeq,
static inline int nvme_process_cq(struct nvme_queue *nvmeq)
{
- return nvme_poll_cq(nvmeq, NULL);
+ DEFINE_IO_COMP_BATCH(iob);
+ int found;
+
+ found = nvme_poll_cq(nvmeq, &iob);
+ if (iob.req_list)
+ nvme_pci_complete_batch(&iob);
+ return found;
}
static irqreturn_t nvme_irq(int irq, void *data)
--
2.33.1
