Ebook · Cloud cost optimization

Optimizing cloud infrastructure costs with load testing: find the waste before it reaches your bill

Five load testing capabilities that expose over-provisioning, slow autoscaling, and cost regressions, plus six ready-to-run test scenarios for FinOps and platform teams.

Key capabilities

Load testing is a cost lever, not just a resilience check

Modern load testing platforms do more than generate virtual users. Five capabilities let engineering and platform teams tackle cloud cost directly, by showing where infrastructure is oversized, where autoscaling reacts too late or too much, and where a release quietly made everything more expensive.

Each capability below includes an example of how it works in Gatling Enterprise Edition.

01

Generate realistic load patterns to reveal hidden inefficiencies

Benefit: understand how your system behaves under realistic user conditions, not synthetic extremes.

Realistic load modeling is the foundation of meaningful cost and performance insight. Before production traffic arrives, teams can reproduce actual usage patterns:

Baseline steady state

Average daily traffic

Gradual ramp

Organic growth

Traffic spike

Stress on autoscaling and queues

Sustained plateau

Long-term resource consumption

By increasing virtual users step by step while watching response times, error rates, and resource utilization, teams can pinpoint the load level where performance starts degrading or costs accelerate. That's the data you need to refine autoscaling thresholds, right-size clusters, or tune database connections before users are affected.

Example: one simulation, several load shapes (JavaScript)
const injectionProfile = (scn) => { switch (testType) { case "capacity": return scn.injectOpen( incrementUsersPerSec(vu).times(4) .eachLevelLasting({ amount: duration, unit: "minutes" }) .separatedByRampsLasting(4) .startingFrom(10) ); case "soak": return scn.injectOpen(constantUsersPerSec(vu).during({ amount: duration, unit: "minutes" })); case "stress": return scn.injectOpen(stressPeakUsers(vu).during({ amount: duration, unit: "minutes" })); case "breakpoint": return scn.injectOpen(rampUsersPerSec(0).to(vu).during({ amount: duration, unit: "minutes" })); case "ramp-hold": return scn.injectOpen( rampUsersPerSec(0).to(vu).during({ amount: rampDuration, unit: "minutes" }), constantUsersPerSec(vu).during({ amount: duration, unit: "minutes" }) ); case "smoke": return scn.injectOpen(atOnceUsers(1)); default: return scn.injectOpen(atOnceUsers(vu)); } };
With Gatling Enterprise Edition

Injection profiles cover ramps, spikes, plateaus, and custom shapes, so tests reproduce the traffic patterns you actually expect.

02

Scale load generation across regions and services

Benefit: test distributed architectures the way they're actually used in production.

For global applications and microservices, load from a single location isn't enough. Network latency, regional routing, and service boundaries create bottlenecks that only appear under distributed, high-scale conditions. Running load generators in several regions at once lets teams:

  • Identify geo-specific bottlenecks, such as slow routing through one region
  • Validate multi-region autoscaling behavior
  • Reproduce complex traffic topologies, like API calls from mobile users worldwide
  • Measure the cost impact of scaling distributed services under real conditions
AP · Hong KongAP · TokyoAP · MumbaiAP · SydneyEurope · Dublin+ your private locations
With Gatling Enterprise Edition

Distributed load generation orchestrates one test across many load generators and regions, to mimic real-world, large-scale traffic.

03

Track cost and performance regressions over time

Benefit: make infrastructure tuning a continuous, data-driven process.

Cost inefficiencies creep in gradually. A new feature increases API call volume, or a database query gets more expensive. These regressions are easy to miss without a long-term view. Scheduled load tests (daily, weekly, or per release) create a baseline, and comparing successive runs shows what changed:

Slower responses under the same loadPotential performance regression
Higher resource use for similar trafficPotential cost regression
Changes in scaling behaviorDrift in autoscaling configuration or architecture

This takes consistent test naming, controlled environments, and a clear comparison method. Run-to-run comparison is what separates real regressions from normal variability.

With Gatling Enterprise Edition

Run trends and run comparison overlay multiple test results, chart percentile response times and throughput over time, and surface regressions quickly.

04

Connect performance metrics with infrastructure behavior

Benefit: correlate application performance under load with infrastructure signals to uncover hidden waste.

Load tests produce rich data: response times, error rates, throughput, connection metrics. Without infrastructure and APM data next to it, the picture is incomplete. With an APM platform such as Datadog or Dynatrace in the loop, teams can match:

Latency spikesCPU or memory saturation on specific services
Scaling delaysSlow pod scheduling or delayed capacity provisioning
Connection failuresNetwork or TLS bottlenecks

These correlations reveal inefficient scaling, such as autoscaling rules that add compute only after latency has already spiked, and components that are over-provisioned for the load they actually handle.

With Gatling Enterprise Edition

APM integrations put load test results next to infrastructure telemetry in real time.

05

Validate cost thresholds automatically

Benefit: stop cost and performance regressions from reaching production with automated gates.

Manual review of load test results doesn't scale. For FinOps to be sustainable, cost and performance checks have to be automated, and that's what assertions are for. They turn expectations into quantitative thresholds:

  • "P95 latency stays below 500 ms at 10,000 concurrent users."
  • "The error rate stays under 1% on every endpoint."
  • "Throughput for key transactions stays within the expected range."

When a test breaks a threshold, the pipeline fails or flags it. Over time, thresholds can track cost projections too, for example by rejecting configurations that trigger unnecessary scale-ups at low load.

Example assertions (JavaScript)
// The max response time of all requests is under 100 ms setUp(scn.injectOpen(injectionProfile)) .assertions(global().responseTime().max().lt(100)); // No request has more than 5% failures setUp(scn.injectOpen(injectionProfile)) .assertions(forAll().failedRequests().percent().lte(5.0)); // "MyRequest" in group "MyGroup" has exactly 0% failures setUp(scn.injectOpen(injectionProfile)) .assertions(details("MyGroup", "MyRequest").failedRequests().percent().is(0.0)); // Throughput for group "MyGroup" stays between 100 and 1,000 requests per second setUp(scn.injectOpen(injectionProfile)) .assertions(details("MyGroup").requestsPerSec().between(100.0, 1000.0));
With Gatling Enterprise Edition

Detailed assertions gate CI/CD pipelines, so only configurations that meet your SLOs and cost targets move forward.

Cost-efficient testing practices

Make cost optimization part of engineering culture

Even the best tools fall short without disciplined practices. Mature teams use five habits so load testing informs cost decisions systematically, not through one-off audits.

01

Source-controlled tests

Simulations stored in Git are reproducible and versioned.

02

Configuration as code

Packages and simulations defined as code can be deployed, audited, and rolled back automatically.

03

Clear run names

Meaningful names like api-checkout-baseline-v3 make history and comparisons easier to read.

04

Scheduled baselines

Weekly or pre-release runs catch regressions early.

05

Shared results

Dashboards and shared links let leadership and finance follow trends without technical tooling.

With Gatling Enterprise Edition

Build-from-Git, configuration as code for packages and simulations, and run labels help teams industrialize their testing. Load testing becomes part of platform engineering and FinOps, not an isolated QA task.

Practical test scenarios

Six tests that cut cloud waste

Load testing isn't only about resilience. These six scenarios help platform and engineering teams uncover infrastructure inefficiencies and support FinOps goals.

Autoscaling spike test

Goal
Check how quickly and efficiently autoscaling responds to sudden surges.
Scenario
Use spike injection profiles from several regions to simulate flash traffic.
FinOps impact
Reveals scaling delays and overreactions, so rules can be tuned to cut both wasted capacity and degraded performance.

Baseline steady-state test

Goal
Measure real infrastructure usage under normal conditions.
Scenario
Run a constant load that mirrors average daily traffic in staging or pre-production.
FinOps impact
Highlights oversized environments and idle capacity you can reduce without affecting users.

Peak capacity ramp-up test

Goal
Find the exact load at which your system starts to degrade.
Scenario
Ramp virtual users from baseline to peak and beyond, watching latency, errors, and resource use.
FinOps impact
Enables evidence-based sizing for peak periods instead of expensive just-in-case provisioning.

Off-hours idle load test

Goal
Detect resources that stay active unnecessarily during low-traffic periods.
Scenario
Run very light constant loads at night or on weekends to watch scale-down behavior.
FinOps impact
Uncovers chances to automate shutdowns or scale-down schedules for non-production environments.

Pre-release cost regression test

Goal
Catch cost-impacting performance changes before deployments go live.
Scenario
Run the same baseline load against each release candidate and compare resource use and response times with the previous release.
FinOps impact
Stops silent cost regressions, like features that add backend load, from reaching production.

Multi-region load distribution test

Goal
Understand the cost and performance impact of serving traffic from several regions.
Scenario
Launch distributed load tests from different regions to simulate global user behavior.
FinOps impact
Helps optimize regional placement, routing, and autoscaling to cut latency and unnecessary cross-region traffic costs.
Pro tip

Start with one or two of these scenarios on your most critical services. Record baseline results, then use run trends and comparison to track improvements. That turns load testing into a FinOps feedback loop, not a one-time exercise.

Gatling Enterprise Edition

Choosing the right platform for modern load testing

Distributed systems, global users, and fast release cycles take more than generating virtual users. Gatling Enterprise Edition is built around five pillars that cover the whole performance engineering lifecycle.

Analyze smarter and act faster

Real-time visibility with dashboards, trend comparisons, and actionable insights.

Create tests your way

Code, low-code, or no-code: script in JavaScript, TypeScript, or Java, import Postman, or design visually.

Unlock automation

Trigger simulations from CI/CD or the API, apply stop criteria, and gate releases with performance thresholds.

Collaborate and share results

RBAC, SSO, quotas, and shared reports. Share results in Slack, Teams, or Jira.

Deploy load generators anywhere

Run tests from Gatling-managed regions, your own cloud, or on-prem.

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The five capabilities, the code samples, and all six FinOps test scenarios.

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