On 12/16/2021 11:08 AM, Christoph Hellwig wrote:
On Wed, Dec 15, 2021 at 09:24:21AM -0700, Jens Axboe wrote:
+ spin_lock(&nvmeq->sq_lock);
+ while (!rq_list_empty(*rqlist)) {
+ struct request *req = rq_list_pop(rqlist);
+ struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+
+ memcpy(nvmeq->sq_cmds + (nvmeq->sq_tail << nvmeq->sqes),
+ absolute_pointer(&iod->cmd), sizeof(iod->cmd));
+ if (++nvmeq->sq_tail == nvmeq->q_depth)
+ nvmeq->sq_tail = 0;
So this doesn't even use the new helper added in patch 2? I think this
should call nvme_sq_copy_cmd().
I also noticed that.
So need to decide if to open code it or use the helper function.
Inline helper sounds reasonable if you have 3 places that will use it.
The rest looks identical to the incremental patch I posted, so I guess
the performance degration measured on the first try was a measurement
error?
giving 1 dbr for a batch of N commands sounds good idea. Also for RDMA host.
But how do you moderate it ? what is the batch_sz <--> time_to_wait
algorithm ?
