Linux 5.8 Prepped To Make Use Of TPAUSE Instruction With New Intel CPUs

TPAUSE is the new instruction supported by Intel's Tremont microarchitecture and beyond. TPAUSE allows for an optimized state that can provide low wake-up latency compared to existing delay mechanisms. With Linux 5.8, the kernel will begin making use of TPAUSE where supported.

The Timed Pause instruction already saw patches for enabling new instructions like TPAUSE and UMONITOR/UMWAIT back for Linux 4.19. But now queued in x86/timers ahead of the upcoming Linux 5.8 cycle are the changes for the kernel to actually begin making use of TPAUSE for more power efficient suspension of execution. TPAUSE supports modes of low-latency but with less power savings or another state for greater power savings but with longer wake-up latency. That is configurable via an MSR while the default behavior is the greater power savings.

With a patch set to go for the upcoming Linux 5.8 cycle is supporting a TPAUSE delay for the kernel where supported.

Tremont cores with TPAUSE availability can be found in Intel Atom "Snow Ridge" processors and forthcoming Lakefield processors.