主函数main解析和sat类头文件分析
- 一、简介
- 二、入口函数main.cc剖析
- 三、SAT压力测试对象接口和数据结构
- 总结
一、简介
stressapptest（简称SAT）是一种用于在Linux系统上测试系统稳定性和可靠性的工具，通过产生CPU、内存、磁盘等各种负载来测试系统的稳定性。
本文主要剖析入口函数main()的流程，以及stressapptest的核心类Sat的头文件定义。从简单开始，一步步分析各个功能模块。
二、入口函数main.cc剖析
main.cc的代码块如下，主打一个简洁。通过注释的方式剖析大致流程。
#include "sattypes.h"
#include "sat.h"
// 入口函数。
int main(int argc, char **argv) {// Sat是stressapptest的核心类，通过SatFactory返回创建的对象指针。Sat *sat = SatFactory();if (sat == NULL) {logprintf(0, "Process Error: failed to allocate Sat object\n");return 255;}// 创建sat对象后，必须先解析命令行参数if (!sat->ParseArgs(argc, argv)) {logprintf(0, "Process Error: Sat::ParseArgs() failed\n");sat->bad_status();} else if (!sat->Initialize()) {// 接着进行相关的初始化logprintf(0, "Process Error: Sat::Initialize() failed\n");sat->bad_status();} else if (!sat->Run()) {// 初始化完成后即可运行压力测试logprintf(0, "Process Error: Sat::Run() failed\n");sat->bad_status();}// 测试完成后通过这个打印结果sat->PrintResults();// 进行一些清理工作if (!sat->Cleanup()) {logprintf(0, "Process Error: Sat::Cleanup() failed\n");sat->bad_status();}// 检查Sat的状态，以便返回给终端方便用户了解状态int retval;if (sat->status() != 0) {logprintf(0, "Process Error: Fatal issue encountered. See above logs for ""details.\n");retval = 1;} else if (sat->errors() != 0) {retval = 1;} else {retval = 0;}// 释放Sat类的内存delete sat;return retval;
}
执行流程图：
SatFactory()的实现在sat_factory.cc中，声明在sat.h里。非常的简单，就是new一个对象，然后返回。
#include "sat.h" // NOLINTSat *SatFactory() {return new Sat();
}
三、SAT压力测试对象接口和数据结构
这是一个为系统级压力测试和分析而设计的综合压力测试类。这里先了解功能函数接口，实现细节后面再分析。
class Sat代码的简单分析：
- 代码定义了一个名为Sat的类，其中包含各种成员函数和数据成员。
- 有一个构造函数Sat()、一个析构函数~Sat()和几个成员函数来解析参数、初始化、运行测试、打印结果和清理。
- 类还包含获取和返回空页和满页的函数、访问器函数和操作错误注入的函数。
- 包含初始化、线程管理、分析和报告函数。
- 数据成员用来保存配置参数、控制标志、内存和测试配置、资源和结果。
- 代码使用了各种c++特性，如enmu类型、vector 和 map。
- 利用多线程使用pthreads，并包含特定的方法不同类型的压力测试，如内存，文件IO，网络IO，磁盘IO, CPU压力，和缓存一致性测试。
- 类定义并使用多个队列结构进行页面管理，它同时使用单锁和细锁队列实现。
- 包含各种不允许的复制和赋值操作。
// sat.h : sat stress test object interface and data structures#ifndef STRESSAPPTEST_SAT_H_
#define STRESSAPPTEST_SAT_H_#include <signal.h>#include <map>
#include <string>
#include <vector>// This file must work with autoconf on its public version,
// so these includes are correct.
#include "finelock_queue.h"
#include "queue.h"
#include "sattypes.h"
#include "worker.h"
#include "os.h"// SAT stress test class.
class Sat {public:// Enum for page queue implementation switch.// 用于页面队列的单锁和细锁模式切换。SAT_ONELOCK和SAT_FINELOCK有不同的实现方式。enum PageQueueType { SAT_ONELOCK, SAT_FINELOCK };Sat();virtual ~Sat();// Read configuration from arguments. Called first.// 从命令行参数中读取配置参数，这个必须在所有的操作前调用。bool ParseArgs(int argc, char **argv);virtual bool CheckGoogleSpecificArgs(int argc, char **argv, int *i);// Initialize data structures, subclasses, and resources,// based on command line args.// Called after ParseArgs().// 根据命令行参数初始化数据结构、子类和资源。在ParseArgs()之后调用。bool Initialize();// Execute the test. Initialize() and ParseArgs() must be called first.// This must be called from a single-threaded program.// 执行测试。Initialize()和ParseArgs()必须先调用；而且不能被多线程或多次调用。bool Run();// Pretty print result summary.// Called after Run().// Return value is success or failure of the SAT run, *not* of this function!// 打印结果概括。bool PrintResults();// Pretty print version info.// 打印版本信息bool PrintVersion();// Pretty print help.// 打印帮助信息virtual void PrintHelp();// Clean up allocations and resources.// Called last.// 清理分配和资源。最后才调用。bool Cleanup();// Abort Run(). Only for use by Run()-installed signal handlers.// 中止运行。仅供Run()使用，而且安装了信号处理才能使用。void Break() { user_break_ = true; }// Fetch and return empty and full pages into the empty and full pools.bool GetValid(struct page_entry *pe); // 获取任何有效的pagebool PutValid(struct page_entry *pe); // 放置有效page,bool GetEmpty(struct page_entry *pe); // 获取带有任何tag的空pagebool PutEmpty(struct page_entry *pe); // 放置带有任何tag的空pagebool GetValid(struct page_entry *pe, int32 tag); // 获取任何有效的page,并且指定tagbool GetEmpty(struct page_entry *pe, int32 tag); // 获取指定tag的空page// Accessor functions.// 一些获取成员变量值的函数。int verbosity() const { return verbosity_; }int logfile() const { return logfile_; }int page_length() const { return page_length_; }int disk_pages() const { return disk_pages_; }int strict() const { return strict_; }int tag_mode() const { return tag_mode_; }int status() const { return statuscount_; }void bad_status() { statuscount_++; }int errors() const { return errorcount_; }int warm() const { return warm_; }bool stop_on_error() const { return stop_on_error_; }bool use_affinity() const { return use_affinity_; }int32 region_mask() const { return region_mask_; }// Semi-accessor to find the "nth" region to avoid replicated bit searching..// 查找“第n”区域以避免重复bit位搜索。int32 region_find(int32 num) const {for (int i = 0; i < 32; i++) {if ((1 << i) & region_mask_) {if (num == 0)return i;num--;}}return 0;}// Causes false errors for unittesting.// Setting to "true" causes errors to be injected.// 造成单元测试错误。设置为“true”会导致注入错误。void set_error_injection(bool errors) { error_injection_ = errors; }bool error_injection() const { return error_injection_; }protected:// Opens log file for writing. Returns 0 on failure.// 打开并初始化log文件bool InitializeLogfile();// Checks for supported environment. Returns 0 on failure.// 检查环境是否已知并且可以安全运行。bool CheckEnvironment();// Allocates size_ bytes of test memory.// 分配要在其上运行测试的内存bool AllocateMemory();// Initializes datapattern reference structures.// 设置对data pattern的访问bool InitializePatterns();// Initializes test memory with datapatterns.// 初始化页面列表，并用datapatterns填充页面。bool InitializePages();// Start up worker threads// 启动SAT的任务线程.virtual void InitializeThreads();// Spawn worker threads.// 生成工作线程。void SpawnThreads();// Reap worker threads.// 通知并获得工作线程void JoinThreads();// Run bandwidth and error analysis.// 处理工作线程数据获取带宽信息和错误结果。可以在这里添加更多的方法。virtual void RunAnalysis();// Delete worker threads.// 删除已使用的工作线程对象。void DeleteThreads();// Return the number of cpus in the system.// 返回机器中实际存在的cpu数量。int CpuCount();// Return the worst-case (largest) cache line size of the system.// 返回机器中实际存在的各级缓存的最坏情况(最大)缓存行大小。int CacheLineSize();// Read int values from kernel file system e.g. sysfs// 从内核文件系统(例如sysfs)中读取int值int ReadInt(const char *filename, int *value);// Collect error counts from threads.// 获取所有线程的总错误计数。int64 GetTotalErrorCount();// Command line arguments.// 命令行参数字符串string cmdline_;// Memory and test configuration.// 内存和测试配置信息int runtime_seconds_; // Seconds to run.运行的时间（秒）int page_length_; // Length of each memory block.每个内存块的长度int64 pages_; // Number of memory blocks.内存块的数量int64 size_; // Size of memory tested, in bytes.测试内存的大小，以字节为单位int64 size_mb_; // Size of memory tested, in MB.测试内存的大小，以MB为单位int64 reserve_mb_; // Reserve at least this amount of memory// for the system, in MB.为系统预留至少多少的内存量，单位是MB。int64 min_hugepages_mbytes_; // Minimum hugepages size.最小的大页面大小int64 freepages_; // How many invalid pages we need.需要多少无效页面。int disk_pages_; // Number of pages per temp file.每个临时文件的页数。uint64 paddr_base_; // Physical address base.物理基地址uint64 channel_hash_; // Mask of address bits XORed for channel.地址位的掩码为通道xor。int channel_width_; // Channel width in bits.以bit为单位的channel位宽。vector< vector<string> > channels_; // Memory module names per channel.每个channel的内存模块名称。// Control flags.volatile sig_atomic_t user_break_; // User has signalled early exit. Used as// a boolean.发出提前退出信号。int verbosity_; // How much to print.打印的数量级int print_delay_; // Chatty update frequency.打印频率或间隔时间int strict_; // Check results per transaction.检查每个事务的结果。int warm_; // FPU warms CPU while copying.int address_mode_; // 32 or 64 bit binary.地址的bit数bool stop_on_error_; // Exit immendiately on any error.一旦出现错误，立即退出。bool findfiles_; // Autodetect tempfile locations.自动检测临时文件位置。bool error_injection_; // Simulate errors, for unittests. 模拟错误，用于memory的单元测试。bool crazy_error_injection_; // Simulate lots of errors.模拟大量错误。uint64 max_errorcount_; // Number of errors before forced exit.允许的最大错误数，当错误数达到这个设定值将强制退出程序int run_on_anything_; // Ignore unknown machine ereor.忽略未知机器bool use_logfile_; // Log to a file.确定要不要向文件中写日志。char logfilename_[255]; // Name of file to log to.日志文件的路径int logfile_; // File handle to log to.日志文件的文件句柄。bool log_timestamps_; // Whether to add timestamps to log lines.是否向日志行添加时间戳。// Disk thread options.int read_block_size_; // Size of block to read from disk.要从磁盘读取的块的大小。int write_block_size_; // Size of block to write to disk.写入磁盘的块大小。int64 segment_size_; // Size of segment to split disk into.要将磁盘分割成的段大小。int cache_size_; // Size of disk cache.磁盘缓存大小。int blocks_per_segment_; // Number of blocks to test per segment.每个段要测试的块数。int read_threshold_; // Maximum time (in us) a read should take// before warning of a slow read.在发出慢读警告之前的最长读时间(单位为us)。int write_threshold_; // Maximum time (in us) a write should// take before warning of a slow write.在发出慢写警告之前的最长读时间(单位为us)。int non_destructive_; // Whether to use non-destructive mode for// the disk test. 无损检测方式进行硬盘测试的标志。// Generic Options.int monitor_mode_; // Switch for monitor-only mode SAT.// This switch trumps most of the other// argument, as SAT will only run error// polling threads.int tag_mode_; // Do tagging of memory and strict// checking for misplaced cachelines.bool do_page_map_; // Should we print a list of used pages?unsigned char *page_bitmap_; // Store bitmap of physical pages seen.uint64 page_bitmap_size_; // Length of physical memory represented.// Cpu Cache Coherency Options.bool cc_test_; // Flag to decide whether to start the// cache coherency threads.int cc_cacheline_count_; // Number of cache line size structures.int cc_cacheline_size_; // Size of a cache line.int cc_inc_count_; // Number of times to increment the shared// cache lines structure members.// Cpu Frequency Options.bool cpu_freq_test_; // Flag to decide whether to start the// cpu frequency thread.int cpu_freq_threshold_; // The MHz threshold which will cause// the test to fail.int cpu_freq_round_; // Round the computed frequency to this// value.// Thread control.int file_threads_; // Threads of file IO.int net_threads_; // Threads of network IO.int listen_threads_; // Threads for network IO to connect.int memory_threads_; // Threads of memcpy.int invert_threads_; // Threads of invert.int fill_threads_; // Threads of memset.int check_threads_; // Threads of strcmp.int cpu_stress_threads_; // Threads of CPU stress workload.int disk_threads_; // Threads of disk test.int random_threads_; // Number of random disk threads.int total_threads_; // Total threads used.bool error_poll_; // Poll for system errors.// Resources.cc_cacheline_data *cc_cacheline_data_; // The cache line sized datastructure// used by the ccache threads// (in worker.h).vector<string> filename_; // Filenames for file IO.vector<string> ipaddrs_; // Addresses for network IO.vector<string> diskfilename_; // Filename for disk IO device.// Block table for IO device.vector<DiskBlockTable*> blocktables_;bool use_affinity_; // Should stressapptest set cpu affinity?int32 region_mask_; // Bitmask of available NUMA regions.int32 region_count_; // Count of available NUMA regions.int32 region_[32]; // Pagecount per region.int region_mode_; // What to do with NUMA hints?static const int kLocalNuma = 1; // Target local memory.static const int kRemoteNuma = 2; // Target remote memory.// Results.int64 errorcount_; // Total hardware incidents seen.int statuscount_; // Total test errors seen.// Thread type constants and typesenum ThreadType {kMemoryType = 0,kFileIOType = 1,kNetIOType = 2,kNetSlaveType = 3,kCheckType = 4,kInvertType = 5,kDiskType = 6,kRandomDiskType = 7,kCPUType = 8,kErrorType = 9,kCCType = 10,kCPUFreqType = 11,};// Helper functions.virtual void AcquireWorkerLock();virtual void ReleaseWorkerLock();pthread_mutex_t worker_lock_; // Lock access to the worker thread structure.typedef vector<WorkerThread*> WorkerVector;typedef map<int, WorkerVector*> WorkerMap;// Contains all worker threads.WorkerMap workers_map_;// Delay between power spikes.time_t pause_delay_;// The duration of each pause (for power spikes).time_t pause_duration_;// For the workers we pause and resume to create power spikes.WorkerStatus power_spike_status_;// For the workers we never pause.WorkerStatus continuous_status_;class OsLayer *os_; // Os abstraction: put hacks here.class PatternList *patternlist_; // Access to global data patterns.// RunAnalysis methodsvoid AnalysisAllStats(); // Summary of all runs.void MemoryStats();void FileStats();void NetStats();void CheckStats();void InvertStats();void DiskStats();void QueueStats();// Physical page use reporting.void AddrMapInit();void AddrMapUpdate(struct page_entry *pe);void AddrMapPrint();// additional memory data from google-specific tests.// google专用的内存统计方法和选项。virtual void GoogleMemoryStats(float *memcopy_data,float *memcopy_bandwidth);virtual void GoogleOsOptions(std::map<std::string, std::string> *options);// Page queues, only one of (valid_+empty_) or (finelock_q_) will be used// at a time. A commandline switch controls which queue implementation will// be used.class PageEntryQueue *valid_; // Page queue structure, valid pages.class PageEntryQueue *empty_; // Page queue structure, free pages.class FineLockPEQueue *finelock_q_; // Page queue with fine-grain locksSat::PageQueueType pe_q_implementation_; // Queue implementation switchDISALLOW_COPY_AND_ASSIGN(Sat);
};Sat *SatFactory();#endif // STRESSAPPTEST_SAT_H_类结构图：
总结
深入剖析了主函数main.cc。主函数的解析包括各个部分的功能和调用关系，以及参数解析和初始化过程。接着，文章详细分析了SAT压力测试对象的接口和数据结构。通过对SAT类头文件的分析，介绍了SAT类中定义的各种方法和成员变量，以及对应的功能和用途。在这些剖析过程中，读者可以深入了解stressapptest程序的内部结构和实现细节，有助于进一步理解该程序的运行机制和性能压力测试的实现原理。
