CSR: Small: Accelerating Microprocessor Post-Silicon Diagnosis with Statistical Inference

在现代复杂的微处理器中发现漏洞是一项关键而艰巨的任务，必须巧妙地掌握这项任务，才能将设计从第一块芯片推向市场。逃脱的漏洞可能会导致一家数字硅公司的灭亡。同时，在第一个硅原型上寻找设计错误缺乏预硅仿真框架所提供的可观察性、可控性和可重复性。使过程进一步复杂化的是，在实际硅中出现的许多错误是复杂的异步交互和/或电气异常的结果，这些异常通常不容易或经常重复。由于这些挑战，在早期的硅中调试这些“转瞬即逝的bug”是一种黑暗的艺术，如果调试过程进行得不顺利，可能会严重影响设计进度。本项目研究解决方案，以支持这些最具挑战性的后硅验证错误的有效诊断，这些错误只是偶尔出现。这些错误可能是功能、时间或电气错误，也可能是遗漏的制造缺陷。该方法需要在芯片上放置轻量级仪器，以便在原型测试执行期间收集数据。然后使用统计推理算法对数据进行离线分析，以快速将验证工程师指向有问题的组件。该研究探索了一系列的想法，以找到最有前途的仪器和算法进行分析。这项研究工作的结果使半导体公司能够在提供高质量产品的同时缩短上市时间，同时降低漏失bug的发生率；反过来，这项工作使社会受益，因为它为电子工业打开了进一步的规模和增长。

Finding bugs in modern complex microprocessors is a critical and daunting task that must be deftly mastered to move designs from first silicon to launch. Escaped bugs may lead to the demise of a digital silicon company. At the same time, looking for design errors on first silicon prototypes lacks the observability, controllability and repeatability afforded by pre-silicon simulation frameworks. To complicate the process further, many of the bugs that manifest in real silicon are the result of complex asynchronous interactions and/or electrical anomalies that are often not easily or frequently repeatable. Because of these challenges, debugging these "fleeting bugs" in early silicon is a black art that can significantly impact design schedules if the debugging process does not proceed smoothly.This project investigates solutions to support the efficient diagnosis of these most challenging post-silicon validation bugs, those that manifest only occasionally. These bugs may be functional, timing or electrical errors, or also missed manufacturing defects. The approach entails placing lightweight instrumentation on-chip to collect data during a prototype's test executions. The data is then analyzed offline using statistical inference algorithms to quickly point verification engineers to offending components. The research explores a range of ideas to find the most promising instrumentation and algorithms for analysis. The results of this research effort allow semiconductor companies to shorten their time to market while delivering high quality products, with low incidence of escaped bugs; in turn, the work benefits society in that it unlocks further scaling and growth for the electronics industry.