soup/soup_cli/utils/gpu.py

116 lines
3.5 KiB
Python

"""GPU detection, memory calculation, and auto batch size."""
import math
def detect_device() -> tuple[str, str]:
"""Detect available device. Returns (device_string, human_name)."""
try:
import torch
if torch.cuda.is_available():
name = torch.cuda.get_device_name(0)
return "cuda", name
if hasattr(torch.backends, "mps") and torch.backends.mps.is_available():
return "mps", "Apple Silicon (MPS)"
except ImportError:
pass
return "cpu", "CPU (no GPU detected)"
def get_gpu_info() -> dict:
"""Get GPU memory info."""
try:
import torch
if torch.cuda.is_available():
total = torch.cuda.get_device_properties(0).total_mem
total_gb = total / (1024**3)
return {
"memory_total": f"{total_gb:.1f} GB",
"memory_total_bytes": total,
"gpu_count": torch.cuda.device_count(),
}
if hasattr(torch.backends, "mps") and torch.backends.mps.is_available():
# MPS doesn't expose memory easily, estimate from system
return {
"memory_total": "shared (Apple Silicon)",
"memory_total_bytes": 0,
"gpu_count": 1,
}
except ImportError:
pass
return {
"memory_total": "N/A (CPU mode)",
"memory_total_bytes": 0,
"gpu_count": 0,
}
def estimate_batch_size(
model_params_b: float,
seq_length: int,
gpu_memory_bytes: int,
quantization: str = "4bit",
lora_r: int = 64,
) -> int:
"""Estimate max batch size that fits in GPU memory.
Conservative estimate — better to start smaller and gradient accumulate.
"""
if gpu_memory_bytes == 0:
return 1 # CPU fallback
gpu_gb = gpu_memory_bytes / (1024**3)
# Rough memory per param based on quantization
bytes_per_param = {"4bit": 0.5, "8bit": 1.0, "none": 2.0} # FP16
bpp = bytes_per_param.get(quantization, 2.0)
# Model memory (static)
model_mem_gb = model_params_b * bpp
# LoRA trainable params (usually ~1-3% of total)
lora_ratio = min(lora_r * 2 / 4096, 0.05) # rough estimate
trainable_mem_gb = model_params_b * 2 * lora_ratio # FP16 for trainable
# Optimizer states (Adam: 2x params)
optimizer_mem_gb = trainable_mem_gb * 2
# Available for activations
overhead_gb = 1.5 # CUDA overhead, fragmentation
available_gb = gpu_gb - model_mem_gb - trainable_mem_gb - optimizer_mem_gb - overhead_gb
if available_gb <= 0:
return 1
# Rough activation memory per sample per token
# ~2 bytes per hidden dim per layer per token for a transformer
activation_per_sample_gb = (seq_length * model_params_b * 0.001) # very rough
activation_per_sample_gb = max(activation_per_sample_gb, 0.5) # minimum 0.5 GB
batch_size = max(1, int(available_gb / activation_per_sample_gb))
# Clamp to power of 2 (common practice)
batch_size = 2 ** int(math.log2(batch_size)) if batch_size > 1 else 1
return min(batch_size, 32) # cap at 32
def model_size_from_name(model_name: str) -> float:
"""Guess model size in billions from model name."""
name_lower = model_name.lower()
size_markers = [
("70b", 70), ("65b", 65), ("34b", 34), ("33b", 33),
("13b", 13), ("8b", 8), ("7b", 7), ("3b", 3),
("1.5b", 1.5), ("1b", 1), ("0.5b", 0.5),
]
for marker, size in size_markers:
if marker in name_lower:
return size
return 7.0 # default guess