Arm introduces TLBID support to the Linux kernel to improve high-core-count CPU performanceArm 为 Linux 内核引入 TLBID 支持，提升高核心数 CPU 性能

IT House News on October 4, Phoronix discovered today that Arm submitted an initial set of patches to the Linux kernel this week to support the upcoming TLBI Domains (TLBID) feature. This technology is designed to reduce the system overhead when high-core processors perform TLB (Translation Lookaside Buffer, conversion lookaside buffer) failure operations, thereby improving the performance of large-scale multi-core Arm systems. IT Home Note: TLB is an important structure used by the processor to cache the results of virtual address to physical address translation. When the operating system needs to invalidate part of an address map, it typically needs to send TLB invalidation instructions to multiple CPU cores. In systems with a large number of cores, significant synchronization and communication overhead can be incurred if a TLB invalidation is performed on the entire system every time. The core change in TLBID is to allow the operating system to perform TLB invalidation only for a subset of CPU cores, rather than having to cover the entire system each time. Arm is improving related support for the Linux kernel, enabling the kernel to send TLBI instructions based on the CPU cores that the process has actually run on, and only let the relevant CPU perform TLB cleanup. This mechanism is primarily targeted at high core count Arm server processors. For server workloads running across a large number of CPU cores, avoiding unnecessary system-wide TLB invalidations is expected to reduce synchronization overhead between processors. However, Arm has not yet announced the actual performance test data of TLBID, so its specific benefits still need to be verified by subsequent hardware and software. In addition to the Linux kernel itself, TLBID support for the ARM64 architecture also requires corresponding instruction support from the compilation tool chain. Related work currently relies on LLVM 23 and newer versions, or GNU Binutils 2.46 and newer versions. The patch submitted by Arm is still in the early stages of development. As relevant architecture specifications, compilers, and Linux kernel support gradually improve, future high-core-count Arm server processors equipped with TLBID are expected to utilize more sophisticated TLB failure mechanisms to reduce memory management overhead in large-scale multi-core systems.