A PTM Responder is permitted to issue PTM Response when it has stored copies of the historical timestamps (t3 - t2) but must request the PTM Master Time from elsewhere. In this case, it is permitted to issue PTM Response messages in response to PTM Request Messages while it retrieves the PTM Master Time if that retrieval is expected to take more than 10 μs. 这句话怎么理解
时间: 2024-04-29 13:20:24 浏览: 12
这句话是在讨论一个 PTM 响应器的行为。它的意思是,当 PTM 响应器存储了历史时间戳(t3 - t2)的副本时,可以在没有获得 PTM 主时间的情况下发出 PTM 响应。但是,如果检索 PTM 主时间需要超过 10 微秒,那么在检索 PTM 主时间的同时,该 PTM 响应器可以发出 PTM 响应消息以响应 PTM 请求消息。这意味着,如果 PTM 响应器需要从其他地方获取 PTM 主时间,而这个过程需要一定的时间,那么它可以在等待的同时回应 PTM 请求消息,以提高系统的响应速度。
相关问题
• Switch Downstream Ports and Root Ports acting as PTM Responders must respond to each PTM Request Message received at their Downstream Ports with either PTM Response or PTM ResponseD according to the following rules: ◦ A PTM Responder must not send a PTM Response or PTM ResponseD Message without first receiving a PTM Request Message. ◦ Upon receipt of a PTM Request Message, a PTM Responder must attempt to issue a PTM Response or PTM ResponseD Message within 10 μs. ◦ A PTM Responder must issue PTM Response when the Downstream Port does not have valid historical timestamps (t3 - t2) with which to fulfill a PTM Request Message. 翻译
• 作为 PTM Responders 的 Switch Downstream Ports 和 Root Ports 必须根据以下规则响应其收到的每个 PTM Request Message,使用 PTM Response 或 PTM ResponseD: ◦ PTM Responder 必须在先收到 PTM Request Message 后才能发送 PTM Response 或 PTM ResponseD Message。 ◦ 在收到 PTM Request Message 后,PTM Responder 必须在 10 微秒内尝试发出 PTM Response 或 PTM ResponseD Message。 ◦ 当 Downstream Port 没有有效的历史时间戳(t3 - t2)来满足 PTM Request Message 时,PTM Responder 必须发出 PTM Response。
Duplicate TLPs are detected and discarded in the Data Link Layer, whereas PTM messages are identified in the Transaction Layer. In some implementations it may be difficult or excessively complicated to distinguish a duplicate PTM TLP from other duplicate TLPs. Because Upstream Ports are permitted to invalidate their internal PTM context for implementation-specific criteria, a PTM Requester is allowed to invalidate its internal PTM context upon the reception of any duplicate TLP in addition to any duplicate PTM TLP. Similarly, if ePTM is supported, then a PTM Responder is allowed to invalidate its historical timestamps (t2 - t3) upon the reception of any duplicate TLP. 翻译
在数据链路层中,重复的 TLP(Transaction Layer Packets)会被检测并且丢弃,而在事务层中,PTM(Packet Transmission Layer)消息会被识别。在某些实现中,很难或者过于复杂来区分一个重复的 PTM TLP 和其他重复的 TLP。因为上游端口被允许根据特定的实现标准来使其内部的 PTM 上下文失效,所以一个 PTM 请求者可以在接收到任何重复的 TLP 以及重复的 PTM TLP 时使其内部的 PTM 上下文失效。同样,如果支持 ePTM,则一个 PTM 响应者可以在接收到任何重复的 TLP 时使其历史时间戳(t2 - t3)失效。