NVMe & Modern PC and CPU Architecture 1

Typical PC Layout (Intel) Northbridge ◦Memory controller hub ◦Obsolete in Sandy Bridge Southbridge ◦I/O controller hub ◦Platform Controller Hub (PCH) in Intel Core i series DMI (Direct Media Interface) ◦Intel’s proprietary link between northbridge and southbridge ◦Shares many characteristics with PCIe 2/12

AHCI (Advanced Host Controller Interface) Adaptor-to-host side interface (HBA) ◦AHCI supports ◦Advanced features of SATA (adaptor-to-device side interface) ◦System interconnect (host bus) PCI/PCIe ◦Logical translation between two sides Features ◦Queuing interface ◦Power management 3/12

NVMe (Non-Volatile Memory Express) Background ◦Introduction of SSD ◦Performance capabilities are orders of magnitude greater than previous storage devices NVMe ◦Device interface ◦Attach directly to the PCIe bus ◦Feature ◦Highly parallel and highly scalable ◦Namespace 4/12

NVMe Latency NVMe reduces latency overhead by more than 50% ◦SCSI/SAS: 6.0 µs 19,500 cycles ◦NVMe: 2.8 µs 9,100 cycles Credit : Slide from Flash Memory Summit /12

Namespace Partitioning of the physical storage extent into multiple logical storage extents 6/12

NVMe Subsystem Multi-Path I/O and Namespace Sharing ◦One or more controller ◦One or more namespaces ◦One or more PCI Express ports ◦A NV memory storage medium 7/12

PCIe SR-IOV 8/12

PCIe Multi-Path Usage Model 9/12

PCIe External Cabling ePCIe (external PCI express, Cabled PCI express) ◦Specifications released by PCI-SGI in Feb., /12

Intel Processor Architecture Core i series ◦Nehalem ◦FSB -> QPI ◦Southbridge -> PCH (Lynnfield) ◦Sandy Bridge ◦Northbridge disappeared ◦Ivy Bridge ◦22nm die ◦Haswell ◦Transactional Synchronization Extensions (TSX) 11/12

Modern PC Layout & NVMe Sandy Bridge & NVMe ◦PCIe is directly connected to CPU ◦NVMe is able to maximize storage performance 12/12

References A Comparison of NVMe and AHCI, 2012 NVM Express: Unlock Your Solid State Drives Potential, Flash Memory Summit 13/12