基于机器学习的多压多温多参标准单元延迟快速计算方法  

A machine learning-based fast calculation method of multi-voltage,multi-temperature and multi-parameter standard cell delay

作　　者：赵振宇[1] 杨天豪 蒋汶乘 张书政 ZHAO Zhen-yu;YANG Tian-hao;JIANG Wen-cheng;ZHANG Shu-zheng(College of Computer Science and Technology,National University of Defense Technology,Changsha 410073;College of Electronic Science and Technology,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学计算机学院,湖南长沙410073 [2]国防科技大学电子科学学院,湖南长沙410073

出　　处：《计算机工程与科学》2023年第8期1331-1338,共8页Computer Engineering & Science

基　　金：国家自然科学基金(62034005)。

摘　　要：标准单元库是芯片设计、分析和验证的基础,其生成需要耗费大量时间和服务器资源,因此供应商往往只提供少量端角的标准单元库。但是,芯片性能、功耗、可靠性等指标的设计需要标准单元在多种电压、温度和参数(驱动强度、沟道长度和阈值电压等)下的延迟信息。为快速实时计算多种端角下标准单元的延迟,提出了一种基于机器学习的多压多温多参标准单元延迟计算方法。通过深入研究影响标准单元延迟的因素,从28 nm工艺标准单元库和时序报告中提取数据构成数据集,使用机器学习算法训练并校准得到了标准单元延迟计算模型。模型的建立仅耗时数分钟,远远低于模拟方法耗费的时间(通常数百小时)。该模型对未知电压下单元延迟的计算平均误差为1.542 ps,未知温度下单元延迟的计算平均误差为1.814 ps,不同参数下单元延迟的计算平均误差为2.202 ps,静态时序分析流程中单元延迟预测偏差小于3%。该方法可以快速实时地计算单元延迟,并且具有较高的准确性,可以应用于签核前的多场景快速时序分析。Standard cell library is the foundation of chip design,analysis,and verification,and its generation requires a lot of time and server resources.Therefore,vendors often only provide standard cell libraries under a few corners.However,the design of chip performance,power consumption,and reliability requires delay information of standard cells under multiple voltages,temperatures,and parameters(such as drive strength,channel length,and threshold voltage).To quickly and accurately calculate the delay of standard cells under multiple corners,this paper proposes a machine learning-based method for multi-voltage,multi-temperature,and multi-parameter standard cell delay calculation.By studying the factors that affect the delay of standard cells in depth,data sets are extracted from the 28nm process standard cell library and timing reports.Machine learning algorithms are used to train and calibrate the standard cell delay calculation model.The establishment of the model takes only a few minutes,which is much less than the time consumed by simulation methods(usually hundreds of hours).The average calculation error of the model is 1.542 ps for unknown voltage cell delay,1.814 ps for unknown temperature cell delay,and 2.202 ps for cell delay under different parameters.The prediction error of cell delay in the static timing analysis process is less than 3%.This method can quickly and accurately calculate the delay of standard cells in real-time and can be applied to fast timing analysis under multiple scenarios before sign-off.

关 键 词：电子设计自动化 标准单元库 门延迟计算 机器学习 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]