从CXL1.1中Host和Device的点对点连接,到CXL2.0支持单级Switch的互联,再到CXL3.0的多级交换网络,CXL 3.1 在互联上不局限于树状拓扑的层次化路由(Hierarchy-Base Routing,HBR),而是采用基于端口的路由(Port-Based Routing,PBR),进一步扩展,追求以更高的效率连接更多的设备。 图5 CXL互联所处的层次以及演进过程 对CXL...
CXL支持高效互联,允许设备通过直接P2P访问绕过主机,减少了数据访问延迟,下图展示了相关估计延迟,CXL在缩短延迟方面显示出了巨大潜力,对于跨越内存障碍具有重要意义。 CXL技术为Host-to-Device和Device-to-Device的高效互联提供了基础。其工作原理如下: Port Based Routing (PBR) ID获取:CXL允许主机或设备通过连接到基于CX...
Based Routing(HBR) switch ⚫ Limitation of PBR switch connection ⚫ An Upstream port of a PBR switch can only be connected to a root port of the Host ⚫ In other words, it cannot be connected to a downstream port of an HBR switch ⚫ No way to avoid failure route ⚫ ...
such as 256B and Port Based Routing (PBR) Flits, CXL.mem Back-Invalidation, Dynamic Capacity Devices (DCD), LD-FAM and G-FAM Devices, Global Integrated Memory (GIM), Multi-Headed (MH) Devices, Hierarchy Based Routing (HBR) and Port Based Routing (PBR), Direct Peer-to-Peer Routing and...
The CXL fabric uses a port-based routing technology, allowing up to 4,096 different devices to connect. These devices include CPU Hosts, GPUs, and memory devices. It also allows devices to communicate directly with each other without needing to go through a central "shared host." This ...
Ultimately, the biggest differentiator may be the number of nodes supported. CXL’s addressing mechanism, which the Consortium calls Port Based Routing (PBR), supports up to 2^12(4096) devices. So a CXL setup can only scale so far, especially as accelerators, attached memory, and othe...
“Now it can handle port-based routing, which allows for a scale-out deployment. The switching fabric is not subject to traditional tree-based hierarchies,” said Ternullo. “It allows cross-domain access for hosts and devices with a device capable to access up to 4,096 hosts or other ...
Not unlike how small amounts of “hot” data was worthy of the expense of flash storage when NAND was rather pricey, CXL also opens the door for routing data to different memory and storage resources. “One can make appropriate choices on enabling the right memory based on the...
先前CXL 2.0只支援單層的交換連接架構,而CXL 3.0則提供多層的交換連接架構,進而能支援網格(Mesh)、環狀(Ring)等非樹狀的交織(Fabrics)連接架構,並搭配基於連接埠的路由尋址架構(Port Based Routing,PBR),可支援多達4,096個節點,且每個節點可以是主機CPU或周邊裝置,藉此將能組成非常龐大、複雜的CXL連接環境。
exclusive access（但是 NVIDIA 毕竟还是对 CPU 和 OS 缺少控制，要是我做 page-fault-based CC，肯定...