LLM Inference Observability

See Inside Your LLM Inference Engine

Diagnose slow requests, KV cache misses, scheduler bottlenecks, batching inefficiencies, and GPU waste across vLLM, SGLang, TensorRT-LLM, Ray Serve, and KubeRay.

Your current monitoring tells you that inference is slow. We show you why — from request queue to GPU execution.

trace · req_7f92 · live
Request
Gateway0.1ms
Router0.3ms
Inference Engine
Scheduler
KV CacheMISS
Prefill2.2s
Decode1.1s
GPU
latency-breakdown · req_7f92
Total Latency7.2s
Queue Time3.4s
Prefill Time2.2s
Decode Time1.1s
NCCL Wait0.5s
Root Cause
Cache miss + queue saturation
KV cache eviction from concurrent tenant workload. Batch depth exceeded scheduler limit during prefill phase.

The Gap

Your Current Monitoring Stops Too Early

Traditional LLM Observability
What you see today
Latency increased
Tokens increased
Cost increased
Errors increased
Visible stack
User Request
App Trace
LLM API Call
Latency / Cost / Tokens
Inference Engine Observability
What you need to see
Was the request waiting in queue?
Was prefill the bottleneck?
Was decode slow?
Did the KV cache miss?
Was batching inefficient?
Was the GPU underutilized?
Was NCCL communication blocking?
Full stack visible
User Request
Queue
Scheduler
Batch Formation
KV Cache
Prefill
Decode
GPU / NCCL

Application observability shows what your app did. Inference observability shows what your infrastructure did.

Product

One Product for the Critical Path of LLM Inference

Request Explainability

Understand every millisecond of an inference request — queue, prefill, decode, streaming, and GPU.

KV Cache Intelligence

See cache hits, misses, evictions, reuse, and cost savings at the request, model, and tenant level.

Scheduler Visibility

Understand queueing, batching, starvation, and throughput drops inside the engine scheduler.

GPU & Memory Observability

Correlate inference behavior with GPU utilization, memory pressure, and idle time.

Distributed Inference Debugging

Trace bottlenecks across tensor parallelism, pipeline parallelism, and NCCL communication.

Routing & Autoscaling Signals

Expose engine-aware metrics for smarter routing, replica selection, and capacity decisions.

Multi-Engine Telemetry

Normalize metrics across vLLM, SGLang, TensorRT-LLM, Ray Serve, and more into one canonical model.

Request Explainability

Every Slow Request Comes With a Root Cause

Instead of seeing only 'Request latency: 7.2s', see exactly where every millisecond was spent — from queue admission through decode completion.

Features

  • Per-request latency breakdown
  • Queue / prefill / decode decomposition
  • TTFT and TPOT attribution
  • Request-to-engine trace correlation
  • Root-cause labels
  • Request replay and comparison
  • p50 / p95 / p99 request analysis

Buyer Value

Reduce p99 latency
Debug slow requests faster
Identify app vs engine vs GPU blame
Give platform teams request-level evidence
root-cause · req_7f92
Request IDreq_7f92
Total Latency7.2s
Time breakdown
Queue Time3.4s
Prefill Time2.2s
Decode Time1.1s
NCCL Wait0.5s
Root Cause
High queue depth caused by batch fragmentation.
KV cache miss increased prefill time. Scheduler stalled during context switch.
p50 latency2.1s
p95 latency5.8s
p99 latency7.2s

KV Cache Intelligence

Know Whether Your KV Cache Is Saving Money or Silently Failing

KV cache behavior directly impacts TTFT, throughput, and GPU cost. Most teams only see basic utilization — not why cache performance changes.

Features

  • KV cache hit rate
  • Prefix cache hit rate
  • Cached token attribution
  • Cache misses by tenant, model, prompt family
  • Cache evictions and fragmentation
  • Cache residency time
  • Cost savings from cache hits

Buyer Value

Reduce GPU spend
Improve TTFT
Find cache-unfriendly workloads
Tune routing for cache locality
Detect fragmentation before incidents
kv-cache · status
Hit Rate71%
Cached Tokens1.2B
GPU Hours Saved470
Estimated Savings$23,100
Evictions (24h)18,420
Fragmentation RiskHigh
cache-effectiveness · by-tenant
Hit rate by tenant
Tenant A92%
Tenant B64%
Tenant C8%
Prompt family reuse
Support Bot System Prompt89%
Code Review Agent72%
Ad-hoc User Prompts6%

Scheduler Visibility

See Inside the Engine Scheduler

The scheduler controls queueing, batching, throughput, and TTFT. Most teams treat it as a black box — leaving them unable to explain why requests are slow.

Features

  • Waiting and running request counts
  • Queue depth over time
  • Batch size and utilization
  • Prefill / decode balance
  • Request starvation detection
  • Tenant fairness analysis
  • Continuous batching visibility

Buyer Value

Improve throughput
Lower queue time
Tune concurrency limits
Improve batching efficiency
Prevent noisy-neighbor problems
scheduler · state · live
Waiting Requests184
Running Requests52
Batch Capacity64
Batch Utilization81%
Prefill Queue31
Decode Queue21
Queue depth — last 5m
2m ago40
90s ago78
60s ago120
30s ago155
Now184
Scheduler saturation detected
Queue growing faster than drain rate. Batch fragmentation contributing to underutilization.

GPU & Memory Observability

Connect Inference Behavior to GPU Utilization

GPU utilization alone is not enough. You need to know whether the GPU is busy doing useful inference work or waiting on memory, communication, queueing, or scheduling.

Features

  • GPU utilization and memory pressure
  • KV cache memory usage
  • Prefill vs decode GPU load
  • GPU idle and wait time
  • OOM risk detection
  • Per-model GPU cost attribution
  • Activation memory pressure

Buyer Value

Increase GPU utilization
Reduce wasted GPU capacity
Catch memory pressure before OOMs
Understand compute vs memory vs communication bounds
gpu · node-01 · gpu-0
Utilization94%
Memory Used78%
KV Cache Used83%
Decode LoadHigh
Prefill LoadMedium
NCCL Wait (p95)180ms
GPU time breakdown
Useful Decode Work46%
Prefill Work28%
Queue-Induced Waste9%
NCCL Wait7%
Cache Miss Overhead6%
Idle / Fragmentation4%

Distributed Inference Debugging

Understand Bottlenecks Across GPUs, Nodes, and Parallelism Groups

As models scale across GPUs and nodes, inference problems become distributed-systems problems. Tensor-parallel imbalance, pipeline bubbles, and NCCL overhead are invisible without the right instrumentation.

Features

  • Tensor-parallel imbalance detection
  • Pipeline bubble detection
  • NCCL latency tracking
  • All-reduce / all-gather timing
  • Cross-node communication visibility
  • Ray worker health
  • KubeRay pod correlation

Buyer Value

Debug multi-GPU inference
Find communication bottlenecks
Improve model-parallel efficiency
Reduce wasted GPU time
Support larger models with confidence
tensor-parallel · tp_group_01
GPU utilization + wait time
GPU 094% util · 40ms wait
GPU 191% util · 45ms wait
GPU 253% util · 210ms wait
GPU 349% util · 230ms wait
Imbalance detected inside tensor-parallel group
pipeline-stages · model-01
Stage 191% busy
Stage 288% busy
Stage 342% busy
Stage 439% busy
Pipeline bubble detected after Stage 2
nccl · communication
AllReduce p5042ms
AllReduce p95210ms
AllReduce p99430ms
Interconnect bottleneck affecting decode latency

Routing & Autoscaling Signals

Make Routing and Scaling Decisions With Engine-Aware Metrics

CPU and GPU utilization are not enough for LLM routing and autoscaling. Inference routing needs engine-level signals — queue depth, KV cache pressure, TTFT trends, and batch utilization.

Features

  • Routing-ready metrics
  • Autoscaling-ready metrics
  • Replica health scoring
  • Load-aware routing signals
  • KV-aware routing signals
  • Capacity forecasts
  • Scale-up / scale-down recommendations

Buyer Value

Improve TTFT
Avoid overloaded replicas
Increase cache-aware routing
Prevent over-scaling
Reduce GPU cost
routing-signals · replica-selection
Replica A
QueueHigh
KV Cache92%
TTFT2.8s
Replica B ← Recommended
QueueLow
KV Cache61%
TTFT1.1s
Route next request to Replica B
Lower queue depth and available KV capacity predict faster TTFT and lower cache eviction risk.
Engine-aware signals available
Queue depth
Running requests
KV cache pressure
TTFT trend
Batch utilization
Tenant load

Multi-Engine Telemetry

One Telemetry Model Across Every Inference Engine

Every engine exposes different metrics with different names and semantics. This product normalizes them into one consistent, canonical inference schema.

Features

  • Engine-specific collectors
  • Canonical inference schema
  • Metric and trace normalization
  • Request ID propagation
  • Prometheus ingestion
  • OpenTelemetry export
  • Grafana / Datadog / New Relic compatibility

Buyer Value

Avoid vendor lock-in
Compare engines fairly
Migrate between engines safely
Standardize dashboards across teams
One observability layer for all backends
telemetry-normalization
Canonical Metric: queue_time
vLLMwaiting_time_seconds
SGLangqueue_latency
TensorRT-LLMrequest_queue_time
Ray Servereplica_queue_time
KServequeue_duration_seconds
Normalized As
llm.request.queue_time
Export targets
Prometheus
OpenTelemetry
Grafana
Datadog
New Relic
CloudWatch

Integrations

Fits Into the Stack You Already Use

This is not a Datadog or Grafana replacement. It is the missing inference-engine telemetry layer — sending better data into the observability tools your team already uses.

Inference Engines

vLLMSGLangTensorRT-LLMllama.cppLMDeployMLC LLM

Orchestration

Ray ServeKubeRayKServeKubernetesGateway API

Telemetry

PrometheusOpenTelemetryGrafanaDatadogNew RelicCloudWatchAzure MonitorGoogle Cloud Observability

Infrastructure

NVIDIA DCGMKubernetes metricsNode exporterGPU metrics

Send better inference telemetry into the observability tools your team already uses.

Incident Response

From “The Model Is Slow” to Root Cause in Minutes

before · without inference observability
Alertp99 latency increased
Current workflow
1.Check app logs
2.Check gateway logs
3.Check Grafana
4.Check GPU dashboard
5.Check engine logs
6.Guess at batch size
7.Guess at cache pressure
8.Restart pods
MTTR: unknown. Root cause: unclear.
after · inference observability
Incidentp99 latency increased
Root Cause
Queue saturation caused by KV cache fragmentation.
Evidence
Queue time↑ 4.2×
Cache hit rate78% → 31%
Batch utilization84% → 49%
GPU utilizationHigh
Recommended Action
Route tenant X to separate replica pool
Increase KV cache allocation
Reduce max active sequences temporarily

Cost & Capacity Planning

Turn Engine Telemetry Into GPU Cost Decisions

Inference cost is shaped by queueing, batching, cache reuse, GPU utilization, and distributed overhead — not just token volume. See exactly where GPU time goes and where money is being wasted.

Features

  • Cost per request, tenant, and model
  • Cost per cached token
  • GPU hours saved by cache
  • GPU waste detection
  • Capacity forecasting
  • Replica sizing recommendations
  • Batch size and context-length impact analysis

Buyer Value

Lower GPU spend
Improve margins
Plan capacity accurately
Understand tenant-level economics
Tune workloads for cost efficiency
gpu-cost-breakdown · cluster
Where GPU time goes
Useful Decode Work46%
Prefill Work28%
Queue-Induced Waste9%
NCCL Wait7%
Cache Miss Overhead6%
Idle / Fragmentation4%
Recoverable waste22%
Potential savingsEst. $18,000/mo
Cost per request
Cost (avg)$0.0042
Cost (p99)$0.0218
Cache-hit savings$0.0031 saved/req

Architecture

Engine-Native Telemetry Without Replacing Your Stack

architecture · data-flow
vLLM / SGLang / TensorRT-LLM
Any supported inference engine
Engine Collectors
Metrics, traces, logs, runtime state
Inference Telemetry Layer
Normalization, correlation, analysis
Canonical Metrics + Traces
Consistent schema across all engines
Dashboards / Alerts / Recommendations
Root cause, routing, scaling
Datadog / Grafana / New Relic / Cloud
Your existing observability stack

Engine Collectors

Collect metrics, traces, logs, and runtime state from inference engines.

Telemetry Normalizer

Converts engine-specific signals into a canonical inference schema.

Request Correlator

Connects gateway request IDs, app traces, engine traces, and GPU metrics.

Analysis Engine

Detects bottlenecks, regressions, cache failures, and scheduler issues.

Recommendation Layer

Suggests routing, scaling, cache, and concurrency changes.

Export Layer

Sends data to Prometheus, OpenTelemetry, Grafana, Datadog, New Relic, or cloud observability tools.

Differentiation

Built for Inference Infrastructure, Not Just LLM Applications

CapabilityGeneric APM / LLM ObservabilityThis Product
App tracesStrongSupported
Token usageStrongSupported
Prompt loggingStrongSupported
Request latencyStrongDeep breakdown
Queue / prefill / decode visibilityLimitedNative
KV cache intelligenceLimitedNative
Scheduler visibilityLimitedNative
Batch efficiencyLimitedNative
Tensor-parallel visibilityLimitedNative
NCCL bottleneck detectionLimitedNative
Engine-normalized telemetryLimitedNative
Routing / autoscaling signalsLimitedNative

We do not replace your observability stack. We make it inference-aware.

Use Cases

Built for the Problems LLM Platform Teams Actually Face

Debug p99 latency

Find whether latency comes from queueing, prefill, decode, cache misses, or GPU communication.

Reduce TTFT

Identify queue pressure, cache misses, and prefill bottlenecks that delay time to first token.

Improve GPU utilization

See whether GPUs are doing useful inference work or waiting on scheduler, memory, or network.

Tune KV cache behavior

Find cache misses, fragmentation, evictions, and tenant-level cache inefficiency.

Optimize batching

Understand batch size, batch utilization, fragmentation, and scheduler behavior.

Plan capacity

Forecast GPU needs based on request volume, context length, cache reuse, and decode throughput.

Improve routing

Route requests based on queue depth, cache locality, replica health, and engine pressure.

Debug distributed inference

Find tensor-parallel imbalance, pipeline bubbles, and NCCL communication bottlenecks.

Who Uses It

For the Teams Operating LLMs in Production

LLM Platform Teams

Operate vLLM, SGLang, TensorRT-LLM, Ray Serve, and Kubernetes-based inference at scale.

Infrastructure Engineers

Debug GPU utilization, memory pressure, networking, and distributed serving behavior.

SRE Teams

Reduce incident resolution time, improve alert quality, and build operational confidence.

ML Engineers

Understand how model behavior — context length, output length, batch size — affects infrastructure performance.

FinOps Teams

Attribute GPU cost by model, tenant, cache behavior, and request type. Find and fix wasted capacity.

Get Started

Stop Guessing Why Inference Is Slow

Get request-level, engine-level, and GPU-level visibility across your LLM serving stack.