_2025-05-23_16：55：05_	2025-05-23 16：55：05
PCIe的流量控制 - 知乎
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TAGs:设备与驱动 PCI_PCIe 流控
Summary: PCIe's Flow Control is a mechanism in the Data Link Layer that ensures the receiving Transaction Layer has the capacity to receive Transmission Line Packets (TLPs). The Flow Control process involves regular exchange of credit information between the Data Link Layers of the communicating devices. Each device's Buffer capacity is represented in credits, with one credit equating to 4DW of TLP Payload or one TLP Header. The devices exchange Flow Control DLLPs, which carry the latest credit information, to manage the flow of TLPs towards the Data Link Layer. The interval between these credit updates is crucial, as a long interval may leave the buffer empty but prevent the sending of new TLPs, while a short interval may consume significant bandwidth and reduce overall utilization.PCIe 的流控制是数据链路层中的一种机制，可确保接收事务层具有接收传输线数据包 （TLP） 的能力。流控制过程涉及通信设备的数据链路层之间的定期信用信息交换。每个设备的缓冲区容量以积分表示，一个积分等于 4DW 的 TLP 有效载荷或一个 TLP 标头。这些设备交换流控制 DLLP，这些 DLLP 携带最新的信用信息，以管理 TLP 流向数据链路层。这些信用更新之间的间隔至关重要，因为较长的间隔可能会使缓冲区为空，但会阻止发送新的 TLP，而较短的间隔可能会消耗大量带宽并降低整体利用率。