BF16 in FlashAttention: monitor gradient stability
On September 29, 2026, a technical work reported that BF16 rounding in FlashAttention can break a softmax gradient symmetry and cause explosions near the end of training. The authors propose GProj as a correction.
Source: Arredondamento BF16 e instabilidade de gradientes no FlashAttention (arxivb.org). Text prepared with AI from this source.
What happened and what to do
On September 29, 2026, a technical work on fused attention kernels in BF16 reported that BF16 rounding in FlashAttention can break a softmax gradient symmetry. According to the authors, this can cause gradients to explode near the end of training; their proposed correction is GProj.
Companies training models with this kind of kernel can implement gradient stability checks and compare runs with and without the proposed correction. A monitoring routine can record signs of instability during training and help the team assess the impact before changing its configuration.
How the consultancy can help
Wendelmaques can diagnose the training workflow and instability risks, define a validation scope, and implement monitoring and stability checks on the company's infrastructure.
Next step
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