Architectural Implications of Agentic AI Workflows
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Architectural Implications of Agentic AI Workflows Jirong Yang† , Peizhe Liu† , Chaojie Zhang∗ , Jovan Stojkovic†
arXiv:2608.04458v1 [cs.AI] 5 Aug 2026
†
The University of Texas at Austin
∗
Microsoft Azure
tomation [29]. Projections place it among the fastest-growing consumers of datacenter capacity in the coming years [18]. Despite this popularity, the implications of agentic AI for server architecture remain underexplored. Researchers have been optimizing servers for traditional, CPU-centric services such as web serving, key-value stores, and data analytics [15], [21], [24], [27], [30], [32], [33], [37], [49], [60]–[64], [66], and, more recently, the inference of a single monolithic LLM, where dense tensor computation on an accelerator dominates while the host merely feeds it [3], [35], [41], [42], [53], [70], [81]. Agentic execution differs from both. A task no longer maps to a single tensor computation or a request-response service. Instead, it unfolds as a data-dependent graph of many model calls, tool invocations, and control decisions that orchestration software assembles on the host. Thus, execution spans the accelerator and multiple host-side components (CPU, memory system, network, and runtime) and grows complex as applications add agents and deepen their coordination. Although a nascent body of systems work has begun to build agentic frameworks [10], [11], [31], [36], [75], we lack fundamental architectural understanding of how these workloads exercise real hardware and whether servers designed for the two older targets are adequate. To reason systematically about such highly diverse workloads, we first develop a taxonomy along platform-relevant dimensions of agentic AI: how agents are orchestrated, how their workflows are structured, and how models are composed. Guided by the taxonomy, we perform the first architectural characterization of agentic AI through both a production study across the fleet of our hyperscaler, Microsoft Azure, and a controlled study of diverse open-source frameworks, spanning diverse use cases. Our main insight is that agentic AI creates highly fragmented execution, while the dimensions in our taxonomy determine how this fragmentation manifests as heterogeneous resource demand. Since host-side orchestration and tools separate successive model calls, the CPU enters the critical path and each task repeatedly crosses the CPU–GPU boundary. The orchestration mechanism governs how control passes among agents. Execution structure shapes the pattern of host load: long periods of low utilization can be punctuated by bursts toward saturation when workflow stages release groups of tool calls. Model composition determines how evenly a workflow utilizes the accelerator pool, potentially saturating some GPUs while leaving others idle. Even within the same taxonomy class, workloads vary substantially in offered load and the tasks they solve, further widening the range of resource needs. Consequently, conventional, uniformly provisioned servers are ill-suited to agentic AI in three ways. First, fragmentation
Abstract—Agentic AI, where LLMs autonomously plan, invoke tools, and coordinate across agents to solve complex tasks, is an emerging class of datacenter workloads. However, its architectural implications remain largely unexplored. To close this gap, we organize agentic workflows through a taxonomy and present the first architectural characterization of agentic AI using both a production study across the fleet of our hyperscaler and a controlled study of representative open-source frameworks. Our study shows that agentic execution is fundamentally fragmented and heterogeneous. Each request expands into a workflow of LLM inferences, tool invocations, and orchestration decisions that repeatedly crosses the CPU–GPU boundary. Our taxonomy explains how this fragmentation turns into resource demand. As orchestration and tools run on the host, the CPU sits on the critical path. The execution structure sets the load over time, which stays low with sudden bursts when a stage releases its tools. The model composition sets how evenly the workflow uses the GPUs, often saturating some while leaving others idle. Diversity in tasks and tools widens this range even further. These characteristics expose three architectural mismatches of conventional uniform servers. Fragmented execution strands CPU and GPU capacity despite bursty demand. Different software roles make homogeneous CPU provisioning inefficient. Finally, multiplexing many agents onto shared cores degrades microarchitectural locality and increases coordination overhead. Guided by these findings, we derive implications for agentic servers and examine them through Agora, our prototype for commodity servers. Agora dynamically harvests idle CPU cores for co-located throughput work, while protecting agentic tail latency against tool spikes. It also oversubscribes GPU memory by placing more agents on each GPU, prefetching the next agent’s state to hide swap latency. To match the machine to the heterogeneous roles, Agora pools cores by role and applies affinityaware scheduling to restore locality. Finally, Agora automatically tunes all of these mechanisms to the running workload. These techniques substantially improve CPU and GPU utilization and per-server throughput while preserving agent tail latency. Our insights also identify key directions for future server architectures for agentic AI.
I. I NTRODUCTION The way large language models (LLMs) are deployed is changing. Traditionally, LLM serving systems have optimized each model invocation as an independent request: the system consumes a prompt and produces a response [3], [16], [39], [47], [53], [74], [81], [84]. However, a growing class of applications now embeds one or more models in an iterative control loop. At each step, the application uses model inference to interpret the current state, select the next action, such as invoking a tool or delegating a subtask, observe the result, and continue until the task is complete. This agentic mode of execution powers applications in software engineering [22], deep research [13], scientific discovery [50], and enterprise au-
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strands resources: CPUs and GPUs remain underutilized on average yet experience short bursts of near-saturation, leaving substantial capacity idle between bursts. Second, the three host roles (schedulers, orchestrators, and runners) exhibit sharply different resource profiles, so a single homogeneous pool of cores cannot serve all of them efficiently. Third, multiplexing many agents on shared cores degrades microarchitectural locality, as they evict one another’s cache lines and branchpredictor state, increasing pipeline stalls. As the nature and severity of these inefficiencies vary with the workflow, load, and task, no single static configuration suits them all; the server must instead adapt to each workload. Guided by these findings, we derive three design principles for servers running agentic AI. We examine each through a case study implemented in Agora, our prototype for commodity servers. First, on the host side, servers should reclaim the temporal slack from fragmented execution. Agora harvests idle CPU cores for co-located throughput work while protecting agents from sudden tool bursts. Second, on the accelerator side, servers should reclaim the idle capacity rather than dedicating exclusive GPU access to fixed agents. Agora harvests this capacity by consolidating agents onto fewer GPUs, exploiting agents that share model state or are never active at the same time so that busy and idle devices are balanced. Third, host cores should be partitioned by software roles and scheduled to preserve task locality, rather than managed as a single homogeneous pool. Agora isolates and right-sizes the control plane and the bursty runner pool, and pins tasks within the runner pool to preserve cache and branch-predictor locality. We implement the three case studies on open-source agentic frameworks and evaluate them on real hardware against static, workload-agnostic configurations. CPU harvesting recovers 95% of a co-located workload’s standalone throughput and increases host CPU utilization by 30% while limiting agent slowdown to under 3%. GPU harvesting frees a third of the GPUs while raising generation throughput by 82% and cutting tail latency by 2.5×. Role-aware pooling reduces the tools’ CPU demand by up to 46% and worst-case tool latency by 13%, while retaining 99% of serving throughput. Beyond today’s hardware, our insights also suggest optimizations for future hardware. Dedicated support could offload the frequent scheduling and context-management operations off the host cores. CPU cores could further match hardware capabilities to different host roles, combining energy-efficient cores for lightweight coordination with high-performance cores for compute-intensive tool execution. In summary, this paper makes the following contributions: • The first production architectural characterization of agentic AI, measured across the fleet of a hyperscaler. • A taxonomy that organizes the heterogeneous space of agentic AI workloads along platform-relevant axes, with a characterization of real use cases across its classes. • Three server-design implications, explored through case studies in Agora: harvesting idle CPU cores, harvesting idle GPU capacity by consolidating agents, and managing host cores by role and task locality.
GPU
Host Runner
Orchestrator
Turn start
Scheduler
1 Send request
4 Web search 5 Tool result
LLM Engine
2 Invoke LLM 3 Tool calls
Streamed responses
6
7 Edit files 8 Run/Test 9 Final output
Fig. 1. An example of agentic AI workflow execution.
II. BACKGROUND AND M OTIVATION Agentic AI Workflows. Traditional LLM serving treats model invocation as the primary unit of execution. A serving engine prompts the model with context, decodes output tokens autoregressively, and returns a response [68], [74]. The host prepares, schedules, and dispatches requests, while the accelerator, e.g., GPU, executes model computation [39], [51], [83]. An agent places an LLM inside a control loop. Given a goal, it invokes the model to interpret the current state, plan or reflect, and select a next step. The step may invoke an external tool, such as web search, code execution, or retrieval [4], [52], whose result is included in next model calls [72]. Tools run off the accelerator, on the host or a remote service [36], [72]. As each action depends on the previous one, a user request expands into a workflow: a data-dependent graph whose nodes are model inferences, tool invocations, and control decisions, and whose edges are their dependencies [40], [48]. The number, duration, and dependencies of these steps are determined dynamically at runtime, so execution alternates between accelerator-bound generation and host-bound work that tracks dependencies, marshals state, and invokes tools. Figure 1 shows this fragmented, host-orchestrated execution. Multi-agent applications distribute this workflow across cooperating agents. A coordinator may assign subtasks to specialized agents, e.g., researchers, programmers, reviewers [14], [28]. Agents may exchange results and claim work through messages or shared state. Each maintains its own logical control loop, while multiple agents may share the same model backend. Independent subtasks can execute concurrently, while dependencies and iterative feedback serialize others. Agentic Serving Systems. Researchers have been extensively optimizing LLM inference serving. Continuous batching [74], KV-cache management [39], optimized attention kernels [16], [83], disaggregated prefill and decode [53], all raise the throughput of the inference engine. These techniques optimize the inference-serving plane. Agentic workflows open a richer optimization space defined by dependencies among model invocations and tool calls. A growing body of systems work exploits this structure. Speculative agent execution runs likelynext actions ahead of time and discards mispredictions [73]. Programmable, software-defined serving lets applications express and co-optimize the workflow itself [1]. Agent-aware schedulers efficiently order workflow steps [31], [44], [75].
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TABLE I TAXONOMY OF AGENTIC WORKFLOWS WITH EXAMPLES THAT FALL WITHIN DIFFERENT CATEGORIES AND THEIR IMPLICATIONS FOR PLATFORM DESIGN . Dimension Orchestration
Execution structure
Model composition
Option Hostorchestrated LLMorchestrated
Examples in the current corpus MetaGPT [25]; MAGE [82]; Paper2Code [59]
Sequential
AlphaEvolve [50]; Trae Agent [67]; AccelOpt [77]
Parallel
ReConcile [12]; CORAL [56]; DeLM [45]
Homogeneous
Most frameworks use the same base model by default ToolOrchestra [65]; AOrchestra [58]; AccelOpt [77]
Heterogeneous
OWL [26]; ToolOrchestra [65]; AOrchestra [58]
Agentic CPU. The aforementioned software optimizations still run on unchanged hardware. Agentic execution changes the demands placed on this hardware, particularly on the host CPU. In LLM inference the CPU fills a single role: a scheduler that dispatches inferences to the accelerator. Agentic execution keeps this role and adds two additional logical host roles: an orchestrator that routes messages and state among agents and enforces workflow dependencies, and a runner that executes agent logic and invokes tools [40], [48]. Thus, the CPU becomes far more than a front end for the accelerator. Figure 1 shows how these three roles interleave CPU and GPU work across a workflow. This expansion has led several vendors to advertise “agentic” CPUs and platforms [5], [7], [19]. Yet the architectural requirements of such platforms remain unclear. The research community has also begun to examine the CPU in agentic execution, but primarily at a coarse granularity, reporting aggregate host utilization and end-to-end latency [57], [76]. It remains unknown where the host bottlenecks lie, how they shift across the three roles, what microarchitectural challenges agentic workloads pose, and what server mechanisms these behaviors call for.
Implication for platform design The host exposes the control flow to the runtime, enabling scheduling and prefetching. The model selects or creates agents at runtime, adding inference-driven control decisions. Dependent steps form a critical path; a stalled step delays the whole workflow. Independent agents create concurrent inference and tool bursts, increasing batching and load. A common base model enables shared residency and larger cross-agent batches. Multiple model types must remain available within the workflow, complicating load balancing.
state machine specifies the agents and their dependencies, and the host advances execution according to this logic, as in MetaGPT [25] and later multi-agent systems [59], [82]. In an LLM-orchestrated workflow, a model makes routing decisions at runtime and forwards the decision to the host, so the control flow itself includes model inference, as in OWL [26], AOrchestra [58], and ToolOrchestra [65]. As hostside control logic is visible to the runtime, it exposes workflow dependencies and can enable earlier scheduling and prefetching [75]. LLM orchestration instead places a model inference in the control path: the next step depends on generated output, increasing inference demand and reducing predictability. Execution structure. The second dimension is how the nodes of the workflow graph are arranged over time. In a sequential workflow, each agent depends on the result of the preceding one: at most one node is active at a time, forming a chain [50], [67], [77]. A parallel workflow instead fans out independent subtasks that run concurrently and later synchronize, as in multi-agent debate [12], CORAL [56], and DeLM [45]. This structure shapes the temporal pattern of demand on the host and accelerators. A sequential workflow exposes little independent work, so a delayed inference, tool call, or handoff directly extends its critical path. A parallel workflow exposes multiple ready agents at once, creating opportunities for batching and overlap but also concentrating inference and tool activity into bursts that increase pressure on the system’s resources. Model composition. The third dimension is whether the agents run the same model or a mix. In a homogeneous workflow, all agents draw from the same base model, varying only the prompt, tools, or a lightweight adapter, as most opensource frameworks do by default. A heterogeneous workflow combines models of different kinds or sizes [58], [65], [77], e.g., a small model that plans or routes and a large one that writes code [8], [9], [17]. This distinction directly affects model residency and serving efficiency. A homogeneous workflow creates opportunities to share one resident model across agents and batch their requests, with only the peragent context stored separately, simplifying provisioning and placement. A heterogeneous workflow keeps several models resident, raising GPU-memory pressure, fragmenting batching, and complicating load balancing.
III. A TAXONOMY OF AGENTIC W ORKFLOWS Agentic workflows differ widely across deployments, making it difficult to reason about them as a single class. We take an agent, a multi-turn model–tool loop, as the primitive of analysis, and present a taxonomy of multi-agent workflows. Interactions among such primitives expose platformlevel choices and trade-offs. We organize the space along three orthogonal, platform-relevant dimensions, each placing a distinct demand on the server: who decides what runs next (orchestration), how the steps are arranged in time (execution structure), and how many model families are used in the workflow (model composition). Table I summarizes the taxonomy. These dimensions are not immutable labels, instead, a workflow may combine multiple options or move between them across stages [23], [43], [54], [55]. Thus, the taxonomy captures the dominant behavior that determines server needs. Orchestration. The first dimension is who decides what runs next. In a host-orchestrated workflow, such task is done by the host-side program logic. A programmatic graph or
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IV. C HARACTERIZING AGENTIC AI W ORKLOADS To understand the architectural implications of agentic AI, we characterize it through two complementary lenses. First, we conduct a fleet study of production agentic services running in our hyperscaler, Microsoft Azure, capturing their real workload, tool mix, and resource usage at scale. Second, we perform a controlled study using four representative open-source frameworks covering representative points in our taxonomy, allowing us to isolate root causes and reproduce them. For the fleet study, we collect a 24-hour trace of production agentic requests and attribute time, tool activity, and CPU metrics to software roles (schedulers, orchestrators, and runners). For the controlled study, we evaluate SWE-Agent [71] (a single-agent, sequential, tool-intensive coding workflow), Trae [67] (a sequential coding workflow with long tool chains and three model endpoints), CORAL [56] (a four-agent, parallel, homogeneous-model evolutionary workflow), and Owl [26] (a heterogeneous workforce with a coordinator, six text roles, and vision and speech models). We run them on a server with a 96-core AMD EPYC 7V12 CPU and eight NVIDIA A100 GPUs. We deploy one vLLM instance per agent role while varying concurrency from 1 to 32 tasks. Our studies lead to two findings. First, agentic AI creates highly fragmented and heterogeneous execution across the CPU and GPU (Section IV-A). Second, this execution pattern stresses the server architecture in ways that differ from both traditional cloud services and monolithic LLM inference, manifesting as resource imbalance, poor microarchitectural locality, and increasing coordination overhead (Section IV-B).