Evaluating LLM API Performance: Prompt Cost & Latency Analysis using LLM Gateway

Updated: 2023-12-07

Explore the role of an LLM Gateway in assessing LLM API Prompts from Cost and Latency Perspectives, ensuring efficient and economical Generative AI DevOps processes.

Do you like this article? Follow us on LinkedIn.

Installing Gecholog.ai in Azure?

In our previous article, LLM API Traffic Management, we explored the potential for improved tracking of traffic patterns in applications integrated with APIs from large language models. In the dynamic field of Generative AI, it's vital to understand and manage the interactions between applications and Large Language Models (LLM). Today, we aim to illuminate the significance of an API Gateway specialized in LLMs for evaluating LLM API Performance, with an comparasion of prompts, focusing on cost and latency aspects.

The Crucial Role of LLM Gateway in Cost and Latency Analysis

Assessing the quality of LLM prompts is a complex task. For instance, Microsoft's comprehensive guide, How to Evaluate LLMs: A Complete Metric Framework, along with insights from Seaplane and this Arize article, offers an excellent overview of this challenge. Data derived from a transition point like an infrastructure gateway, when properly set up, can make a significant and efficient contribution to this challenge, particularly in terms of latency and cost. Gateways designed for Large Language Models are becoming an indispensable tool in striking a balance between cost-efficiency and performance of LLM APIs. This equilibrium is crucial for businesses that depend on responses from large language models for their critical operations and services.

Scenario: Reviewing Performance of Prompt Variations

Our LLM API Performance Scenario: Imagine we have three classification prompt candidates that perform similarly in terms of classification accuracy, but we want to evaluate their performance in terms of cost and latency. Lower latency is preferable, as many application developers discover when integrating with large language models; avoiding added latency is often a challenge (as discussed in All the Hard Stuff Nobody Talks About when Building Products with LLMs). Our three prompts are undergoing A/B testing, and each request is tagged to enable performance tracking through the LLM Gateway-generated log.

Pie chart showing AB-testing metrics of three different LLM Prompts tracked by the LLM Gateway

Image: Pie chart showing AB-testing metrics of three different LLM Prompts tracked by the LLM Gateway

Cost Analysis: Maximizing Efficiency via Traffic Analysis

Cost efficiency is a key concern in business operations. A log-generating gateway provides an analytical framework for monitoring and managing the performance and financial aspects of LLM API requests. In our scenario, we can track the cost profiles for different variations of the classification Prompts.

Average Cost and Latency Table for three different LLM Prompts tracked by the LLM Gateway

Table: Average Cost and Latency Table for three different LLM Prompts tracked by the LLM Gateway

In our example, the token consumption of Prompt Simple is 50% of Prompt Reduced, which in turn is 50% of Prompt Full. Assuming similar classification performance, the cost profile aligns with expectations: Each step from Prompt Full to Reduced to Simple reduces token consumption.

Latency Optimization: Enhancing User Experience

Beyond cost, latency is a crucial factor in user experience. LLM Gateways excel at monitoring and optimizing response times from generative APIs, such as those from OpenAI. By analyzing traffic patterns and prompt complexities, these gateways can efficiently track request handling, leading to faster response times. This is particularly valuable in applications requiring real-time interactions, like direct user interactions or automated customer service platforms.

From the example data, an interesting observation emerges from the table above. Although token consumption decreases as expected with each prompt simplification, the average duration of the API request-response cycle is nearly identical for Prompt Full and Prompt Reduced, but it's almost 40% lower for Prompt Simple. This is further highlighted when we analyze the data generated from the LLM Gateway to plot the distribution of response times:

Distribution graph of LLM API request latency for three variations of a Classification Prompt

Image: Distribution graph of LLM API request latency for three variations of a Classification Prompt

The distribution of API response times for Prompt Simple requests is clearly shifted to the left, indicating significantly lower average response times. Despite Prompt Reduced consuming fewer tokens than Prompt Full, their response time distributions are very similar, suggesting that switching between Prompt Full and Reduced has negligible impact on customer experience in terms of latency.

Evidence-Based Examples: Real-World Success Stories

The positive impact of data generated from gateways like Gecholog.ai in managing cost and latency is evident in numerous real-world applications. For instance, a leading e-commerce platform utilized their logs to optimize LLM-powered IVR interactions. By refining the prompt structure and payload, the platform achieved a 30% reduction in API costs and a 25% improvement in response times.

A Shift in Generative AI Ops and DevOps Tools Space

The integration of LLM Gateways into DevOps tools signifies a significant shift in how businesses engage with AI technologies. These gateways offer a layer of analysis and optimization for LLM API interactions, empowering businesses to fully exploit AI's capabilities while upholding cost efficiency and performance standards.

Conclusion: The Strategic Advantage of LLM Gateway in API Management

In conclusion, employing a gateway specialized in managing traffic to and from large language models for evaluating prompts from cost and latency perspectives provides a strategic edge in the realms of Generative AI Ops and DevOps. It ensures that businesses can utilize the power of large language models in a cost-effective and efficient way, leading to improved user experiences and operational excellence. As this technology continues to evolve, the role of data-generating gateways will become increasingly crucial in the landscape of AI-driven business operations.


LLM API PerformanceLLM Gateway

Experience the Future of LLM Integration

Ready to better track your application's use of LLMs with a cloud and model-agnostic LLM Gateway? Sign up for our no-obligation free trial and discover how our solution can elevate your LLM API traffic management.