On 6/28/20 3:44 AM, Baolin Wang wrote: > Move the sg table allocation and free into the init_request() and > exit_request(), instead of allocating sg table when queuing requests, > which can benefit the IO performance. > > Signed-off-by: Baolin Wang<baolin.w...@linux.alibaba.com>
The call to sg_init_table() uses blk_rq_nr_phys_segments in nvme_map_data() with this patch we are blindly allocating SG table with NVME_MAX_SEGS, without any performance numbers it is hard to measure the impact. Can you share performance numbers ? I'm particularly interested in for IOPS/BW/CPU/USAGE/Submission latency and completion latency and perf numbers for the respective function in to determine the overall impact.
