从GPT-2到gpt-oss，深度详解OpenAI开放模型的进化之路

Core Insights - OpenAI has released its first open-weight models, gpt-oss-120b and gpt-oss-20b, since the launch of GPT-2 in 2019, which can run locally due to optimizations [4][5] - The article provides a detailed analysis of the architectural advancements from GPT-2 to gpt-oss and compares it with Qwen3 [4][5] Model Architecture Overview - gpt-oss-20b can run on consumer-grade GPUs with 16 GB RAM, while gpt-oss-120b requires a single H100 processor with 80 GB RAM or more [10] - The architecture of gpt-oss models appears conventional, as leading LLM developers often use similar foundational architectures with minor adjustments [10][11] Changes Since GPT-2 - The article highlights significant changes from GPT-2, including the removal of Dropout, the adoption of RoPE for positional encoding, and the replacement of GELU with Swish/SwiGLU [20][22][29] - The introduction of Mixture of Experts (MoE) models allows for increased parameter capacity while maintaining efficiency by activating only a subset of experts for each token [39] - Grouped Query Attention (GQA) is introduced as a more efficient alternative to Multi-Head Attention (MHA) [41] - Sliding window attention is applied in gpt-oss to reduce memory usage and computational costs [47] - RMSNorm replaces LayerNorm for better efficiency in large-scale LLMs [52] Comparison with Qwen3 - gpt-oss-20b has a wider architecture with more attention heads, while Qwen3 has a deeper architecture with more transformer modules [69][70] - gpt-oss uses fewer but larger experts compared to Qwen3, which has more smaller experts [72] - Both models utilize grouped query attention, but gpt-oss incorporates sliding window attention to limit context size [82] Additional Insights - gpt-oss models are designed for inference, allowing users to control inference workload easily [93] - The training compute for gpt-oss is estimated at 2.1 million H100 GPU hours, comparable to other large models [92] - The MXFP4 optimization allows gpt-oss models to run on a single GPU, enhancing accessibility [98] - Benchmark results indicate that gpt-oss performs comparably to proprietary models, although it has not yet been extensively tested [101][106]