Introduction

The System Profiler is a performance analysis tool for Kunpeng-powered servers. It collects performance data of processor hardware, operating system (OS), processes, threads, and functions, analyzes system performance metrics, locates system bottlenecks and hotspot functions, and provides tuning suggestions. This tool helps quickly locate and handle software performance problems.

The Tuning Assistant is a tool for tuning Kunpeng-powered servers. It systematically organizes performance metrics and provides guidance for analyzing performance bottlenecks, thus realizing quick tuning.

**Table 1** Task description
Task Type	Description
Tuning analysis	The Tuning Assistant systematically organizes and analyzes performance metrics, hotspot functions, and system configurations to form a system resource consumption chain. It provides guidance for analyzing performance bottlenecks based on tuning paths and gives tuning suggestions and operation guides for each tuning path to implement fast tuning.
Comparison analysis	For the same type of analysis tasks, you can select the same node or different nodes to compare the analysis results. In this way, you can quickly learn the differences between different analysis results, locate performance metric changes, and identify the effect of optimization methods.
HPC cluster check	The tool checks the hardware and software configurations of a specified MPI cluster and provides a report on software and hardware configuration consistency between nodes in the cluster. The configuration items include CPUs, GPUs, interconnection, memory, NICs, drives, OS, kernel, environment variables, MPI/OpenMP, and common HPC dependency libraries. The tool gives tuning suggestions on configurations that do not comply with the best practices of the Kunpeng platform.
HPC application analysis	The tool collects Performance Monitor Unit (PMU) events of the system and the key metrics of OpenMP and MPI applications to help you accurately obtain the serial and parallel time of the parallel region and barrier-to-barrier, calibrated L2 micro-architecture metrics, instruction distribution, L3 usage, and memory bandwidth.
Overall analysis	The tool collects the software and hardware configuration information of the entire system and the running status of system resources, such as CPUs, memory, storage I/O, and network I/O, to obtain performance metrics such as usage, saturation, and errors. These metrics help identify performance bottlenecks. The tool also provides performance tuning suggestions for some metrics based on the benchmark data and experience. The tool checks the hardware, system, and component configurations in big data, database, and distributed storage scenarios, displays configuration items that are not optimal, and analyzes and provides typical hardware configuration and software version information.
Microarchitecture analysis	The tool obtains the running status of instructions on the CPU pipeline based on Arm Performance Monitor Unit (PMU) events. It helps quickly locate the performance bottleneck of the current application on the CPU and modify the programs to maximize the utilization of hardware resources.
Memory access analysis	By analyzing the events related to the CPU's access to the cache and memory, the tool identifies potential performance bottlenecks on memory access, locates the possible causes, and provides tuning suggestions. Memory access statistics analysis Based on the PMU events related to the processor's access to the cache and memory, the tool analyzes the number of access operations, hit rate, and bandwidth, including: Access hit rate and bandwidth of the L1C, L2C, L3C, and TLB. HHA access rate DDR access bandwidth and access operations Miss event analysis This analysis is based on the Arm Statistical Profiling Extension (SPE) capability. SPE samples instructions and records information about triggered events, including accurate PC pointer information. This capability can be used to analyze miss events, such as LLC misses, TLB misses, remote access, and long latency loads, and accurately associate the code that causes the events. Based on the information, you can modify your programs to reduce the probability of certain events and improve performance. False sharing analysis This analysis is based on the Arm SPE capability. SPE samples instructions and records information about triggered events, including accurate PC pointer information. By using SPE for false sharing analysis on services, the tool obtains information about the number and proportion of false sharing times, instruction addresses, code line numbers, and NUMA nodes. Based on the information, you can modify your programs to reduce the probability of false sharing and improve performance. NUMA refined analysis This analysis is based on the Arm SPE capability. SPE samples instructions and records information about triggered events, including accurate PC pointer information. The tool leverages the SPE capability to collect the NUMA performance of all processes in the system, find the top N (for example, N = 10) processes with the poorest NUMA performance and the hotspot memory areas of these processes, and identify the inter-NUMA node memory access statistics matrix and the inter-node memory access imbalance status. Then related tuning suggestions are provided.
I/O analysis	The tool analyzes storage I/O performance. By analyzing block storage devices, the tool obtains performance data such as the number of I/O operations, I/O data size, I/O queue depth, and I/O operation delay, and identifies specific I/O operations, processes, threads, call stacks, and I/O APIs in the application layer. Based on the I/O performance data, the tool provides tuning suggestions.
Process/Thread performance analysis	The tool collects information about the CPU, memory, and storage I/O resources used by processes or threads to obtain metrics, such as the usage, saturation, and number of errors and identify performance bottlenecks of processes and threads. Then, the tool provides tuning suggestions for some metrics based on the benchmark data and experience. The tool also supports analysis of the system call information for a single process.
Resource scheduling analysis	The tool collects the running status of processes and threads to obtain metrics such as the cold flame graph, number of link switchovers, and global proportions, and identifies performance bottlenecks based on the metrics. Then, the tool provides tuning suggestions for some metrics based on the benchmark data and experience. The system call status of a single process can be analyzed.
Hotspot function analysis	The tool analyzes C/C++ program code, identifies performance bottlenecks, and displays hotspot functions. It also displays the function call relationship in flame graphs and provides the tuning path.
Lock and wait analysis	The tool analyzes the lock and wait functions (including sleep, usleep, mutex, cond, spinlock, rwlock, and semaphore) of glibc and open source software, such as MySQL and OpenMP, associates the processes and call sites to which the lock and wait functions belong, and provides tuning suggestions based on existing experience.
Roofline analysis	Helps pinpoint application bottlenecks on a given hardware platform and optimize an application accordingly.
AI Tuning	Leverages Huawei-developed high-performance AI tuning solution to tune applications in database and big data scenarios according to the test case you specify. After the analysis, tuning suggestions on parameter configurations in complex scenarios are provided.

Parent topic: System Profiler