.. _neuron-2-27-0-runtime: .. meta:: :description: The official release notes for the AWS Neuron SDK Runtime component, version 2.27.0. Release date: 12/19/2025. AWS Neuron SDK 2.27.0: Neuron Runtime release notes =================================================== **Date of release**: December 19, 2025 .. contents:: In this release :local: :depth: 2 * Go back to the :ref:`AWS Neuron 2.27.0 release notes home ` Released versions ----------------- - Neuron Driver: ``2.25.4.0`` - Neuron Runtime Library: ``2.29.40.0`` - Neuron Collectives: ``2.29.41.0`` Compatibility Support Tables ---------------------------- **Runtime Version:** 2.29.40.0 The Neuron runtime was tested for the following EC2 instances and configurations: =========================== ============= ============== ================= =============== Instance Family OS Type OS Version Kernel Version GLIBC Version =========================== ============= ============== ================= =============== ``Inf2`` Ubuntu U24 6.14 2.39 ``Inf2`` Ubuntu U22 6.8 2.35 ``Inf2`` Rocky Linux RL9 5.14 2.34 ``Inf2`` Amazon Linux AL2023 6.12 2.34 ``Trn1`` Ubuntu U24 6.14 2.39 ``Trn1`` Ubuntu U22 6.8 2.35 ``Trn1`` Rocky Linux RL9 5.14 2.34 ``Trn1`` Amazon Linux AL2023 6.12 2.34 ``Trn2`` Ubuntu U24 6.14 2.39 ``Trn2`` Ubuntu U22 6.8 2.35 ``Trn2`` Amazon Linux AL2023 6.12 2.34 =========================== ============= ============== ================= =============== **Driver Version:** 2.25.4.0 The Neuron driver was tested for the following EC2 instances and configurations: =========================== ============= ============== ================= =============== Instance Family OS Type OS Version Kernel Version GLIBC Version =========================== ============= ============== ================= =============== ``Inf2`` Ubuntu U24 6.14 2.39 ``Inf2`` Ubuntu U22 6.8 2.35 ``Inf2`` Rocky Linux RL9 5.14 2.34 ``Inf2`` Amazon Linux AL2023 6.12 2.34 ``Inf2`` Amazon Linux AL2 5.10 2.26 ``Trn1`` Ubuntu U24 6.14 2.39 ``Trn1`` Ubuntu U22 6.8 2.35 ``Trn1`` Rocky Linux RL9 5.14 2.34 ``Trn1`` Amazon Linux AL2023 6.12 2.34 ``Trn1`` Amazon Linux AL2 5.10 2.26 ``Trn2`` Ubuntu U24 6.14 2.39 ``Trn2`` Ubuntu U22 6.8 2.35 ``Trn2`` Amazon Linux AL2023 6.12 2.34 ``Trn2`` Amazon Linux AL2 5.10 2.26 =========================== ============= ============== ================= =============== What's New ---------- Neuron Runtime Library 2.29.40.0 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ * Added support for Trainium3 (single node mode) Neuron Driver 2.25.4.0 ^^^^^^^^^^^^^^^^^^^^^^^^ * Added support for Trainium3 Improvements ------------ Neuron Runtime Library 2.29.40.0 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ * Reduced the overhead of reprogramming the Collectives Engine by up to 100x for NEFFs compiled with the ``-O1`` flag. This improves end-to-end performance of these NEFFs by up to 15%. * Reduced NeuronCore branch overhead by up to 3x, decreasing the overhead of starting a NEFF program by up to 5%. * Reduced the overhead of starting a NEFF program by up to 50% with an on-device hardware barrier between ranks. * Improved all-gather latency by up to 35% for messages greater than 1MB in TP8 (LNC2) and TP16 (LNC1) collectives. * Added support for :ref:`NRT Debug Stream APIs `. Bug fixes --------- Neuron Runtime Library 2.29.40.0 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ * Fixed scratchpad page allocation bug that caused excessive page allocations due to page rounding error. * Fixed segfault that occurred when freeing an empty tensor. Previous release notes ---------------------- * :ref:`neuron-2-26-0-runtime`