vllm/vllm/engine/metrics.py

218 lines
8.9 KiB
Python

from vllm.logger import init_logger
from prometheus_client import Counter, Gauge, Histogram, REGISTRY, disable_created_metrics
import time
import numpy as np
from typing import Dict, List
from dataclasses import dataclass
logger = init_logger(__name__)
disable_created_metrics()
# The begin-* and end* here are used by the documentation generator
# to extract the metrics definitions.
# begin-metrics-definitions
class Metrics:
def __init__(self, labelnames: List[str]):
# Unregister any existing vLLM collectors
for collector in list(REGISTRY._collector_to_names):
if hasattr(collector, "_name") and "vllm" in collector._name:
REGISTRY.unregister(collector)
# System stats
self.gauge_scheduler_running = Gauge(
name="vllm:num_requests_running",
documentation="Number of requests currently running on GPU.",
labelnames=labelnames)
self.gauge_scheduler_swapped = Gauge(
name="vllm:num_requests_swapped",
documentation="Number of requests swapped to CPU.",
labelnames=labelnames)
self.gauge_scheduler_waiting = Gauge(
name="vllm:num_requests_waiting",
documentation="Number of requests waiting to be processed.",
labelnames=labelnames)
self.gauge_gpu_cache_usage = Gauge(
name="vllm:gpu_cache_usage_perc",
documentation="GPU KV-cache usage. 1 means 100 percent usage.",
labelnames=labelnames)
self.gauge_cpu_cache_usage = Gauge(
name="vllm:cpu_cache_usage_perc",
documentation="CPU KV-cache usage. 1 means 100 percent usage.",
labelnames=labelnames)
# Raw stats from last model iteration
self.counter_prompt_tokens = Counter(
name="vllm:prompt_tokens_total",
documentation="Number of prefill tokens processed.",
labelnames=labelnames)
self.counter_generation_tokens = Counter(
name="vllm:generation_tokens_total",
documentation="Number of generation tokens processed.",
labelnames=labelnames)
self.histogram_time_to_first_token = Histogram(
name="vllm:time_to_first_token_seconds",
documentation="Histogram of time to first token in seconds.",
labelnames=labelnames,
buckets=[
0.001, 0.005, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.25, 0.5,
0.75, 1.0, 2.5, 5.0, 7.5, 10.0
])
self.histogram_time_per_output_token = Histogram(
name="vllm:time_per_output_token_seconds",
documentation="Histogram of time per output token in seconds.",
labelnames=labelnames,
buckets=[
0.01, 0.025, 0.05, 0.075, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.75,
1.0, 2.5
])
self.histogram_e2e_request_latency = Histogram(
name="vllm:e2e_request_latency_seconds",
documentation="Histogram of end to end request latency in seconds.",
labelnames=labelnames,
buckets=[1.0, 2.5, 5.0, 10.0, 15.0, 20.0, 30.0, 40.0, 50.0, 60.0])
# Legacy metrics
self.gauge_avg_prompt_throughput = Gauge(
name="vllm:avg_prompt_throughput_toks_per_s",
documentation="Average prefill throughput in tokens/s.",
labelnames=labelnames,
)
self.gauge_avg_generation_throughput = Gauge(
name="vllm:avg_generation_throughput_toks_per_s",
documentation="Average generation throughput in tokens/s.",
labelnames=labelnames,
)
# end-metrics-definitions
@dataclass
class Stats:
"""Created by LLMEngine for use by StatLogger."""
now: float
# System stats.
num_running: int
num_waiting: int
num_swapped: int
gpu_cache_usage: float
cpu_cache_usage: float
# Raw stats from last model iteration.
num_prompt_tokens: int
num_generation_tokens: int
time_to_first_tokens: List[float]
time_per_output_tokens: List[float]
time_e2e_requests: List[float]
class StatLogger:
"""StatLogger is used LLMEngine to log to Promethus and Stdout."""
def __init__(self, local_interval: float, labels: Dict[str, str]) -> None:
# Metadata for logging locally.
self.last_local_log = time.monotonic()
self.local_interval = local_interval
# Tracked stats over current local logging interval.
self.num_prompt_tokens: List[int] = []
self.num_generation_tokens: List[int] = []
# Prometheus metrics
self.labels = labels
self.metrics = Metrics(labelnames=list(labels.keys()))
def _get_throughput(self, tracked_stats: List[int], now: float) -> float:
return float(np.sum(tracked_stats) / (now - self.last_local_log))
def _local_interval_elapsed(self, now: float) -> bool:
elapsed_time = now - self.last_local_log
return elapsed_time > self.local_interval
def _log_prometheus(self, stats: Stats) -> None:
# Set system stat gauges.
self.metrics.gauge_scheduler_running.labels(**self.labels).set(
stats.num_running)
self.metrics.gauge_scheduler_swapped.labels(**self.labels).set(
stats.num_swapped)
self.metrics.gauge_scheduler_waiting.labels(**self.labels).set(
stats.num_waiting)
self.metrics.gauge_gpu_cache_usage.labels(**self.labels).set(
stats.gpu_cache_usage)
self.metrics.gauge_cpu_cache_usage.labels(**self.labels).set(
stats.cpu_cache_usage)
# Add to token counters.
self.metrics.counter_prompt_tokens.labels(**self.labels).inc(
stats.num_prompt_tokens)
self.metrics.counter_generation_tokens.labels(**self.labels).inc(
stats.num_generation_tokens)
# Observe request level latencies in histograms.
for ttft in stats.time_to_first_tokens:
self.metrics.histogram_time_to_first_token.labels(
**self.labels).observe(ttft)
for tpot in stats.time_per_output_tokens:
self.metrics.histogram_time_per_output_token.labels(
**self.labels).observe(tpot)
for e2e in stats.time_e2e_requests:
self.metrics.histogram_e2e_request_latency.labels(
**self.labels).observe(e2e)
def _log_prometheus_interval(self, prompt_throughput: float,
generation_throughput: float) -> None:
# Logs metrics to prometheus that are computed every logging_interval.
# Support legacy gauge metrics that make throughput calculations on the vLLM side.
# Moving forward, we should use counters like counter_prompt_tokens, counter_generation_tokens
# Which log raw data and calculate summaries using rate() on the grafana/prometheus side.
# See https://github.com/vllm-project/vllm/pull/2316#discussion_r1464204666
self.metrics.gauge_avg_prompt_throughput.labels(
**self.labels).set(prompt_throughput)
self.metrics.gauge_avg_generation_throughput.labels(
**self.labels).set(generation_throughput)
def log(self, stats: Stats) -> None:
"""Called by LLMEngine.
Logs to prometheus and tracked stats every iteration.
Logs to Stdout every self.local_interval seconds."""
# Log to prometheus.
self._log_prometheus(stats)
# Save tracked stats for token counters.
self.num_prompt_tokens.append(stats.num_prompt_tokens)
self.num_generation_tokens.append(stats.num_generation_tokens)
# Log locally every local_interval seconds.
if self._local_interval_elapsed(stats.now):
# Compute summary metrics for tracked stats (and log them to promethus if applicable).
prompt_throughput = self._get_throughput(self.num_prompt_tokens,
now=stats.now)
generation_throughput = self._get_throughput(
self.num_generation_tokens, now=stats.now)
self._log_prometheus_interval(
prompt_throughput=prompt_throughput,
generation_throughput=generation_throughput)
# Log to stdout.
logger.info(
f"Avg prompt throughput: {prompt_throughput:.1f} tokens/s, "
f"Avg generation throughput: {generation_throughput:.1f} tokens/s, "
f"Running: {stats.num_running} reqs, "
f"Swapped: {stats.num_swapped} reqs, "
f"Pending: {stats.num_waiting} reqs, "
f"GPU KV cache usage: {stats.gpu_cache_usage * 100:.1f}%, "
f"CPU KV cache usage: {stats.cpu_cache_usage * 100:.1f}%")
# Reset tracked stats for next interval.
self.num_prompt_tokens = []
self.num_generation_tokens = []
self.last_local_log = stats.now