raghunc0
model
60616b8
import time
from collections import deque
from contextlib import nullcontext
from typing import Any, Callable, Deque, Dict, Optional
import torch
from lightning import Callback, Fabric, LightningModule, Trainer
from lightning.fabric.accelerators.xla import _XLA_GREATER_EQUAL_2_1
from lightning.fabric.plugins import (
BitsandbytesPrecision,
DoublePrecision,
FSDPPrecision,
HalfPrecision,
MixedPrecision,
Precision,
TransformerEnginePrecision,
XLAPrecision,
)
from lightning.fabric.utilities.rank_zero import rank_zero_only as fabric_rank_zero_only
from lightning.pytorch.plugins import (
DoublePrecisionPlugin,
FSDPPrecisionPlugin,
HalfPrecisionPlugin,
MixedPrecisionPlugin,
XLAPrecisionPlugin,
)
from lightning.pytorch.utilities.rank_zero import rank_zero_only as trainer_rank_zero_only
from torch.utils.flop_counter import FlopCounterMode
from tsai_gpt import GPT
from tsai_gpt.utils import num_parameters
GPU_AVAILABLE_FLOPS = {
# source: https://resources.nvidia.com/en-us-tensor-core/nvidia-tensor-core-gpu-datasheet
# nvidia publishes spec sheet with a 2x sparsity factor
"h100-sxm": {
torch.float64: 67e12,
torch.float32: 67e12,
torch.bfloat16: 1.979e15 / 2,
torch.float16: 1.979e15 / 2,
torch.int8: 3.958e15 / 2,
},
"h100-pcie": {
torch.float64: 51e12,
torch.float32: 51e12,
torch.bfloat16: 1.513e15 / 2,
torch.float16: 1.513e15 / 2,
torch.int8: 3.026e15 / 2,
},
# source: https://www.nvidia.com/content/dam/en-zz/Solutions/Data-Center/a100/pdf/nvidia-a100-datasheet-us-nvidia-1758950-r4-web.pdf
# sxm and pcie have same flop counts
"a100": {torch.float64: 19.5e12, torch.float32: 19.5e12, torch.bfloat16: 312e12, torch.float16: 312e12},
# source: https://www.nvidia.com/content/dam/en-zz/Solutions/Data-Center/a10/pdf/a10-datasheet.pdf
"a10g": {torch.float32: 31.2e12, torch.bfloat16: 125e12, torch.float16: 125e12},
# source: https://images.nvidia.com/content/technologies/volta/pdf/volta-v100-datasheet-update-us-1165301-r5.pdf
"v100-sxm": {torch.float64: 7.8e12, torch.float32: 15.7e12, torch.float16: 125e12},
"v100-pcie": {torch.float64: 7e12, torch.float32: 14e12, torch.float16: 112e12},
"v100s-pcie": {torch.float64: 8.2e12, torch.float32: 16.4e12, torch.float16: 130e12},
# source: https://www.nvidia.com/content/dam/en-zz/Solutions/Data-Center/tesla-t4/t4-tensor-core-datasheet-951643.pdf
# sxm and pcie have same flop counts
"t4": {torch.float32: 8.1e12, torch.float16: 65e12, torch.int8: 130e12},
# https://www.nvidia.com/content/dam/en-zz/Solutions/design-visualization/quadro-product-literature/quadro-rtx-5000-data-sheet-us-nvidia-704120-r4-web.pdf
"quadro rtx 5000": {torch.float32: 11.2e12, torch.float16: 89.2e12},
}
TPU_AVAILABLE_FLOPS = {
# flop count for each TPU generation is the same for all precisions
# since bfloat16 precision is always used for performing matrix operations
# for more info: https://cloud.google.com/tpu/docs/bfloat16#choosing_bfloat16
# source: https://arxiv.org/pdf/1907.10701.pdf
"v2": 45e12,
# source: https://cloud.google.com/tpu/docs/system-architecture-tpu-vm#tpu_v3
"v3": 123e12,
# source: https://cloud.google.com/tpu/docs/system-architecture-tpu-vm#tpu_v4
"v4": 275e12,
# source: https://cloud.google.com/tpu/docs/v5e-training
"v5litepod": 197e12,
}
def get_flops_available(device: torch.device, dtype: torch.dtype) -> Optional[float]:
if device.type == "cuda":
device_name = torch.cuda.get_device_name(device).lower()
if "h100" in device_name and "hbm3" in device_name:
device_name = "h100-sxm"
elif "h100" in device_name and ("pcie" in device_name or "hbm2e" in device_name):
device_name = "h100-pcie"
elif "a100" in device_name:
device_name = "a100"
elif "a10g" in device_name:
device_name = "a10g"
elif "v100-sxm" in device_name:
device_name = "v100-sxm"
elif "v100-pcie" in device_name:
device_name = "v100-pcie"
elif "t4" in device_name:
device_name = "t4"
elif "quadro rtx 5000" in device_name:
device_name = "quadro rtx 5000"
else:
device_name = None
if device_name is not None:
try:
return int(GPU_AVAILABLE_FLOPS[device_name][dtype])
except KeyError:
raise KeyError(
f"flop count not found for {device_name} with dtype: {dtype}; "
"MFU cannot be calculated and reported."
)
elif device.type == "xla":
if _XLA_GREATER_EQUAL_2_1:
from torch_xla._internal import tpu
else:
from torch_xla.experimental import tpu
device_name = tpu.get_tpu_env()["TYPE"].lower()
try:
return int(TPU_AVAILABLE_FLOPS[device_name])
except KeyError:
raise KeyError(
f"flop count not found for {device_name} with dtype: {dtype}; MFU cannot be calculated and reported."
)
return None
# Adapted from https://github.com/mosaicml/composer/blob/f2a2dc820cb75023b9eb7c46fdfd25273712abd0/composer/callbacks/speed_monitor.py
class SpeedMonitorBase:
"""Logs the training throughput and utilization.
+-------------------------------------+-----------------------------------------------------------+
| Key | Logged data |
+=====================================+===========================================================+
| | Rolling average (over `window_size` most recent |
| `throughput/batches_per_sec` | batches) of the number of batches processed per second |
| | |
+-------------------------------------+-----------------------------------------------------------+
| | Rolling average (over `window_size` most recent |
| `throughput/samples_per_sec` | batches) of the number of samples processed per second |
| | |
+-------------------------------------+-----------------------------------------------------------+
| | Rolling average (over `window_size` most recent |
| `throughput/tokens_per_sec` | batches) of the number of tokens processed per second. |
| | This may include padding depending on dataset |
+-------------------------------------+-----------------------------------------------------------+
| | Estimates flops by `flops_per_batch * batches_per_sec` |
| `throughput/flops_per_sec` | |
| | |
+-------------------------------------+-----------------------------------------------------------+
| `throughput/device/batches_per_sec` | `throughput/batches_per_sec` divided by world size |
+-------------------------------------+-----------------------------------------------------------+
| `throughput/device/samples_per_sec` | `throughput/samples_per_sec` divided by world size |
+-------------------------------------+-----------------------------------------------------------+
| | `throughput/tokens_per_sec` divided by world size. This |
| `throughput/device/tokens_per_sec` | may include pad tokens depending on dataset |
| | |
+-------------------------------------+-----------------------------------------------------------+
| | `throughput/flops_per_sec` divided by world size. Only |
| `throughput/device/flops_per_sec` | logged when model has attribute `flops_per_batch` |
| | |
+-------------------------------------+-----------------------------------------------------------+
| | `throughput/device/flops_per_sec` divided by world size. |
| `throughput/device/mfu` | |
| | |
+-------------------------------------+-----------------------------------------------------------+
| `time/train` | Total elapsed training time |
+-------------------------------------+-----------------------------------------------------------+
| `time/val` | Total elapsed validation time |
+-------------------------------------+-----------------------------------------------------------+
| `time/total` | Total elapsed time (time/train + time/val) |
+-------------------------------------+-----------------------------------------------------------+
Notes:
- The implementation assumes that devices are homogeneous as it normalizes by the world size.
- Tokens/sec, flops/sec and MFU do not account for padding tokens if present. We suggest using samples/sec or
batches/sec to measure throughput under this circumstance.
- Be careful when comparing MFU numbers across projects, as this will highly depend on the ``flops_per_batch``.
There is no widespread, realistic, and reliable implementation to compute them.
We suggest using our ``measure_flops`` function, but many other works will use ``estimated_flops`` which
will almost always be an overestimate when compared to the true value.
Args:
window_size (int, optional): Number of batches to use for a rolling average of throughput.
Defaults to 100.
time_unit (str, optional): Time unit to use for `time` logging. Can be one of
'seconds', 'minutes', 'hours', or 'days'. Defaults to 'hours'.
"""
def __init__(
self,
flops_available: float,
log_dict: Callable[[Dict, int], None],
window_size: int = 100,
time_unit: str = "hours",
):
self.flops_available = flops_available
self.log_dict = log_dict
# Track the batch num samples and wct to compute throughput over a window of batches
self.history_samples: Deque[int] = deque(maxlen=window_size + 1)
self.history_wct: Deque[float] = deque(maxlen=window_size + 1)
self.history_lengths: Deque[int] = deque(maxlen=window_size + 1)
self.history_flops: Deque[int] = deque(maxlen=window_size + 1)
self.divider = 1
if time_unit == "seconds":
self.divider = 1
elif time_unit == "minutes":
self.divider = 60
elif time_unit == "hours":
self.divider = 60 * 60
elif time_unit == "days":
self.divider = 60 * 60 * 24
else:
raise ValueError(
f'Invalid time_unit: {time_unit}. Must be one of "seconds", "minutes", "hours", or "days".'
)
# Keep track of time spent evaluating
self.total_eval_wct = 0.0
self.step = -1
def on_train_batch_end(
self,
samples: int, # total samples seen (per device)
train_elapsed: float, # total training time (seconds)
world_size: int,
flops_per_batch: Optional[int] = None, # (per device)
lengths: Optional[int] = None, # total length of the samples seen (per device)
) -> None:
self.step += 1
step = self.step
metrics = {}
self.history_samples.append(samples)
if lengths is not None:
self.history_lengths.append(lengths)
# if lengths are passed, there should be as many values as samples
assert len(self.history_samples) == len(self.history_lengths)
self.history_wct.append(train_elapsed)
if len(self.history_wct) == self.history_wct.maxlen:
elapsed_batches = len(self.history_samples) - 1
elapsed_samples = self.history_samples[-1] - self.history_samples[0]
elapsed_wct = self.history_wct[-1] - self.history_wct[0]
samples_per_sec = elapsed_samples * world_size / elapsed_wct
dev_samples_per_sec = elapsed_samples / elapsed_wct
metrics.update(
{
"throughput/batches_per_sec": elapsed_batches * world_size / elapsed_wct,
"throughput/samples_per_sec": samples_per_sec,
"throughput/device/batches_per_sec": elapsed_batches / elapsed_wct,
"throughput/device/samples_per_sec": dev_samples_per_sec,
}
)
if lengths is not None:
elapsed_lengths = int(self.history_lengths[-1]) - int(self.history_lengths[0])
avg_length = elapsed_lengths / elapsed_batches
metrics.update(
{
"throughput/tokens_per_sec": samples_per_sec * avg_length,
"throughput/device/tokens_per_sec": dev_samples_per_sec * avg_length,
}
)
if flops_per_batch is not None:
# sum of flops per batch across ranks
self.history_flops.append(flops_per_batch * world_size)
if len(self.history_flops) == self.history_flops.maxlen:
elapsed_flops = sum(self.history_flops) - self.history_flops[0]
elapsed_wct = self.history_wct[-1] - self.history_wct[0]
flops_per_sec = elapsed_flops / elapsed_wct
device_flops_per_sec = flops_per_sec / world_size
metrics.update(
{"throughput/flops_per_sec": flops_per_sec, "throughput/device/flops_per_sec": device_flops_per_sec}
)
if self.flops_available:
metrics["throughput/device/mfu"] = device_flops_per_sec / self.flops_available
metrics.update(
{
"time/train": train_elapsed / self.divider,
"time/val": self.total_eval_wct / self.divider,
"time/total": (train_elapsed + self.total_eval_wct) / self.divider,
"samples": samples,
}
)
self.log_dict(metrics, step)
def eval_end(self, eval_elapsed: float) -> None:
self.total_eval_wct += eval_elapsed # seconds
def plugin_to_compute_dtype(plugin: Precision) -> torch.dtype:
if isinstance(plugin, BitsandbytesPrecision):
return plugin.dtype
if isinstance(plugin, (HalfPrecision, MixedPrecision, HalfPrecisionPlugin)):
return plugin._desired_input_dtype
if isinstance(plugin, MixedPrecisionPlugin):
return torch.bfloat16 if plugin.precision == "bf16-mixed" else torch.half
if isinstance(plugin, (DoublePrecision, DoublePrecisionPlugin)):
return torch.double
if isinstance(plugin, (XLAPrecision, XLAPrecisionPlugin)):
return plugin._desired_dtype
if isinstance(plugin, TransformerEnginePrecision):
return torch.int8
if isinstance(plugin, (FSDPPrecision, FSDPPrecisionPlugin)):
return plugin.mixed_precision_config.reduce_dtype
if isinstance(plugin, Precision):
return torch.float32
raise NotImplementedError(plugin)
class SpeedMonitorFabric(SpeedMonitorBase):
def __init__(self, fabric: Fabric, *args: Any, **kwargs: Any) -> None:
dtype = plugin_to_compute_dtype(fabric.strategy.precision)
flops_available = get_flops_available(fabric.device, dtype)
super().__init__(flops_available, fabric.log_dict, *args, **kwargs)
@fabric_rank_zero_only
def on_train_batch_end(self, *args: Any, **kwargs: Any) -> None:
super().on_train_batch_end(*args, **kwargs)
class SpeedMonitorCallback(Callback):
def __init__(self, length_fn: Callable[[Any], int], batch_size: int, **kwargs: Any) -> None:
super().__init__()
self.speed_monitor: Optional[SpeedMonitorBase] = None
self.speed_monitor_kwargs = kwargs
self.length_fn = length_fn
self.batch_size = batch_size
self.eval_t0: int = 0
self.train_t0: int = 0
self.total_lengths: int = 0
def setup(self, trainer: Trainer, pl_module: LightningModule, stage: str) -> None:
if self.speed_monitor is not None:
return # already setup
dtype = plugin_to_compute_dtype(trainer.precision_plugin)
flops_available = get_flops_available(trainer.strategy.root_device, dtype)
self.speed_monitor = SpeedMonitorBase(flops_available, trainer.logger.log_metrics, **self.speed_monitor_kwargs)
@trainer_rank_zero_only
def on_train_start(self, trainer: Trainer, pl_module: LightningModule) -> None:
if trainer.fit_loop._should_accumulate():
return
self.train_t0 = time.perf_counter()
@trainer_rank_zero_only
def on_train_batch_end(
self, trainer: Trainer, pl_module: LightningModule, outputs: Any, batch: Any, batch_idx: int
) -> None:
self.total_lengths += self.length_fn(batch)
if trainer.fit_loop._should_accumulate():
return
train_elapsed = time.perf_counter() - self.train_t0
assert self.speed_monitor is not None
iter_num = trainer.fit_loop.total_batch_idx
assert (measured_flops := pl_module.measured_flops) is not None
self.speed_monitor.on_train_batch_end(
(iter_num + 1) * self.batch_size,
train_elapsed,
# this assumes that device FLOPs are the same and that all devices have the same batch size
trainer.world_size,
flops_per_batch=measured_flops,
lengths=self.total_lengths,
)
@trainer_rank_zero_only
def on_validation_start(self, trainer: Trainer, pl_module: LightningModule) -> None:
self.eval_t0 = time.perf_counter()
@trainer_rank_zero_only
def on_validation_end(self, trainer: Trainer, pl_module: LightningModule) -> None:
eval_elapsed = time.perf_counter() - self.eval_t0
assert self.speed_monitor is not None
self.speed_monitor.eval_end(eval_elapsed)
def flops_per_param(max_seq_length: int, n_layer: int, n_embd: int, n_params: int) -> int:
flops_per_token = 2 * n_params # each parameter is used for a MAC (2 FLOPS) per network operation
# this assumes that all samples have a fixed length equal to the block size
# which is most likely false during finetuning
flops_per_seq = flops_per_token * max_seq_length
attn_flops_per_seq = n_layer * 2 * 2 * (n_embd * (max_seq_length**2))
return flops_per_seq + attn_flops_per_seq
def estimate_flops(model: GPT) -> int:
"""Measures estimated FLOPs for MFU.
Refs:
* https://ar5iv.labs.arxiv.org/html/2205.05198#A1
* https://ar5iv.labs.arxiv.org/html/2204.02311#A2
"""
# using all parameters for this is a naive over estimation because not all model parameters actually contribute to
# this FLOP computation (e.g. embedding, norm). For this reason, the result will be higher by a fixed percentage
# (~10%) compared to the measured FLOPs, making those lower but more realistic.
# For a proper estimate, this needs a more fine-grained calculation as in Appendix A of the paper.
n_trainable_params = num_parameters(model, requires_grad=True)
trainable_flops = flops_per_param(
model.max_seq_length, model.config.n_layer, model.config.n_embd, n_trainable_params
)
# forward + backward + gradients (assumes no gradient accumulation)
ops_per_step = 3 if model.training else 1
n_frozen_params = num_parameters(model, requires_grad=False)
frozen_flops = flops_per_param(model.max_seq_length, model.config.n_layer, model.config.n_embd, n_frozen_params)
# forward + backward
frozen_ops_per_step = 2 if model.training else 1
return ops_per_step * trainable_flops + frozen_ops_per_step * frozen_flops
def measure_flops(model: GPT, x: torch.Tensor) -> int:
"""Measures real FLOPs for HFU"""
flop_counter = FlopCounterMode(model, display=False)
ctx = nullcontext() if model.training else torch.no_grad()
with ctx, flop_counter:
y = model(x)
if model.training:
y.sum().backward()
return flop_counter.get_total_flops()