The simplified precision time protocol significantly reduces the number of exchanges between a server and client, allowing efficient network communication.
Meta has developed a simplified version of its network timing protocol, Precision Time Protocol (PTP), which it has dubbed the Simple Precision Time Protocol (SPTP). Meta said that when subjected to its internal tests, SPTP boasts comparable performance to PTP, but with significant improvements in CPU, memory, and network utilisation.
“In data centres, where communication is typically driven by hundreds of thousands of clients and multicast is not supported, these tradeoffs are very limiting. The simplified protocol significantly reduces the number of exchanges between a server and client, allowing for much more efficient network communication, meaning it can offer the exact same level of synchronisation with a lot fewer resources consumed,” Meta said.
“In a large-scale data center deployment, it can help to combat frequently changing network paths and create savings in terms of network traffic, memory usage, and number of CPU cycles. It will also eliminate a lot of complexity inherited from multicast PTP profiles, which is not necessarily useful in the trusted networks of the modern data centers,” Meta stated in its blog post.
Meta first announced its plan to deploy the protocol in November 2022, using PTP to keep every server in its data centres at the same time in order to avoid delays, errors, and outages. Unlike Network Time Protocol (NTP) which allows for precision within milliseconds, PTP allows for precision within nanoseconds. However, the company now says that PTP wasn’t a “perfect fit” for its data centre deployment due to the excessive network communication the protocol requires, which results in disproportionate memory and CPU usage, strict capacity limits, code complexity, and fragile state transitions.
