Estimating GPT-3 Training FLOPs

I'll estimate the total number of floating point operations (FLOPs) required to train GPT-3 by breaking down the calculation step by step.

Model Architecture Facts

• GPT-3 has approximately 175 billion parameters
• Uses a transformer architecture with multiple layers
• Context length of 2048 tokens
• Trained on approximately 300 billion tokens

Calculating FLOPs per Token

For transformer models, we need to account for operations in:

1. Self-attention mechanisms
2. Feed-forward networks
3. Layer normalization and other operations

For GPT-3, let's use these parameters:

• Embedding dimension (d): ~12,288
• Number of layers (L): ~96
• Context length (s): 2,048

Forward Pass Calculation

For each token in each layer:

• Self-attention: ~4 × d² + 2 × d × s FLOPs
• Feed-forward network: ~8 × d² FLOPs
• Other operations: ~d FLOPs

Total FLOPs per token (forward pass): ≈ L × (12 × d² + 2 × d × s) ≈ 96 × (12 × 12,288² + 2 × 12,288 × 2,048) ≈ 96 × (1.8 × 10⁹ + 5 × 10⁷) ≈ 1.8 × 10¹¹ FLOPs

Backward Pass

The backward pass typically requires about 2× the computation of the forward pass: ≈ 2 × 1.8 × 10¹¹ ≈ 3.6 × 10¹¹ FLOPs

Total FLOPs per token (forward + backward): ≈ 1.8 × 10¹¹ + 3.6 × 10¹¹ ≈ 5.4 × 10¹¹ FLOPs

Total Training FLOPs

Multiply by the total number of tokens processed: ≈ 5.4 × 10¹¹ × 300 × 10⁹ ≈ 1.62 × 10²³ FLOPs

Alternative Calculation

As a sanity check, using a simpler heuristic:

• Each parameter requires ~2-4 FLOPs per token (including forward, backward, and weight update)
• 175B parameters × 4 FLOPs × 300B tokens ≈ 2.1 × 10²³ FLOPs

Conclusion

The total training computation for GPT-3 was approximately 1.6-2.1 × 10²³ FLOPs (160-210 zettaFLOPs).

This massive computational requirement explains why training such models costs millions of dollars and requires specialized supercomputing infrastructure.

To estimate the total number of FLOPs required to train GPT-3, let's break it down into key components.

1. Model Size and Parameters

GPT-3 has 175 billion parameters.

2. FLOPs per Forward and Backward Pass

In deep learning, the FLOPs required for a forward pass and backward pass are estimated as:

• Forward pass: ( 2 imes ) the number of parameters
• Backward pass: ( 2 imes ) the FLOPs of the forward pass

Thus, total FLOPs per training step:

[ ext{Total FLOPs per step} = 6 imes ext{number of parameters} imes ext{tokens per batch} ]

For GPT-3, let's assume 175B parameters and a batch size of 2048 tokens (common for large-scale training).

[ ext{FLOPs per training step} = 6 imes 175 imes 10^9 imes 2048 ]

[ = 2.15 imes 10^{15} ext{ FLOPs per step} ]

3. Total Training Steps

GPT-3 was trained with 300 billion tokens (as per OpenAI's paper).

If the batch size is 2048 tokens, the total number of steps is:

[ ext{Total steps} = rac{300 imes 10^9}{2048} approx 1.46 imes 10^8 ]

4. Total FLOPs Required

Multiplying the FLOPs per step by the total number of steps:

[ ext{Total FLOPs} = (2.15 imes 10^{15}) imes (1.46 imes 10^8) ]

[ approx 3.14 imes 10^{23} ext{ FLOPs} ]

Final Answer:

The estimated total number of FLOPs required to train GPT-3 is about ( 3.14 imes 10^{23} ) floating point operations.