The article focuses on an understudied yet fundamental problem: existing methods typically average the utilization of multiple hardware threads to evaluate the available CPU resources. However, the approach could underestimate the actual usage of the underlying physical core for Simultaneous Multi-Threading (SMT) processors, leading to an overestimation of remaining resources. The overestimation propagates from microarchitecture to operating systems and cloud schedulers, which may misguide scheduling decisions, exacerbate CPU overcommitment, and increase Service Level Agreement (SLA) violations. To address the potential overestimation problem, we propose an SMT-aware and purely data-driven approach namedRemaining CPU(RCPU) that reserves more CPU resources to restrict CPU overcommitment and prevent SLA violations. RCPU requires only a few modifications to the existing cloud infrastructures and can be scaled up to large data centers. Extensive evaluations in the data center proved that RCPU contributes to a reduction of SLA violations by 18% on average for 98% of all latency-sensitive applications. Under a benchmarking experiment, we prove that RCPU increases the accuracy by 69% in terms of Mean Absolute Error (MAE) compared to the state-of-the-art.

Collecting sufficient microarchitecture performance data is essential for performance evaluation and workload characterization. There are many events to be monitored in a modern processor while only a few hardware performance monitoring counters (PMCs) can be used, so multiplexing is commonly adopted. However, inefficiency commonly exists in state-of-the-art profiling tools when grouping events for multiplexing PMCs. It has the risk of inaccurate measurement and misleading analysis. Commercial tools can leverage PMCs, but they are closed source and only support their specified platforms. To this end, we propose an approach for efficient cross-platform microarchitecture performance measurement via adaptive grouping, aiming to improve the metrics’ sampling ratios. The approach generates event groups based on the number of available PMCs detected on arbitrary machines while avoiding the scheduling pitfall of Linux perf_event subsystem. We evaluate our approach with SPEC CPU 2017 on four mainstream x86-64 and AArch64 processors and conduct comparative analyses of efficiency with two other state-of-the-art tools, LIKWID and ARM Top-down Tool. The experimental results indicate that our approach gains around 50% improvement in the average sampling ratio of metrics without compromising the correctness and reliability.