For the latest TLC NAND, one write buffer unit (rwb batch)
needs to be spread over three PUs instead of being allocated
to a single PU for better sequential read performance
since the optimal write size(ws_opt) of 3D TLC NAND is
3 times bigger than the optimal read size(rs_opt).
I added num_interleave_units in 'struct spdk_ftl_conf'
to configure the number of interleaving units per ws_opt.
If num_interleave_units is set as 1, the whole of the ws_opt
blocks are placed sequentially around each PU.
If num_interleave_units is set as N, the 1/N of the ws_opt
blocks are staggered. So consecutively numbered blocks
are separated by ws_opt / num_interleave_units.
The sequential read performance is improved from 1.9GiB/s
up to 2.97GiB/S with this patch on our system. No performance
degradation is observed on sequential writes or
4KB random reads/writes.
Please refer to the Trello card for more details.
https://trello.com/c/Osol93ZU
Change-Id: I371e72067b278ef43c3ac87a3d9ce9010d3fcb15
Signed-off-by: Claire J. In <claire.in@circuitblvd.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/450976
Reviewed-by: Young Tack Jin <youngtack.jin@circuitblvd.com>
Reviewed-by: Konrad Sztyber <konrad.sztyber@intel.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Wojciech Malikowski <wojciech.malikowski@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
658d118c06