Linux Performance and Tuning Linux教学课件.ppt

Linux Performance and Tuning Understanding the Linuxoperating system register Cpu: 10G 73:74 4k, page, page frame(页框) 60-70% 仿真 Monitor OS ? VM Write back(回写) 计算机的体系 运算器 控制器 存储设备 输入设备 输出设备 Cache line 一级缓存 指令缓存 数据缓存 完全关联 Full associative 部分关联 Set associative 直接映射 Direct mapping Schematic interaction of different performance components Linux process management What is a process? A process is an instance of execution that runs on a processor From the kernels point of view, the purpose of a process is to act as an entity to which system resources (CPU time, memory, etc.) are allocated They include a set of resources such as open files and pending signals, internal kernel data, processor state, a memory address space with one or more memory mappings, one or more threads of execution, and a data section containing global variables Process Descriptor and the Task Structure To manage processes, the kernel must have a clear picture of what each process is doing The kernel stores the list of processes in a circular doubly linked list called the task list All processes running on Linux operating system are managed by the task_struct structure, which is also called a process descriptor The task_struct is a relatively large data structure, at around 1.7 kilobytes on a 32-bit machine The process descriptor and task list List Task_structure The Linux process descriptor Process State TASK_RUNNING The process is either executing on a CPU or waiting to be executed TASK_INTERRUPTIBLE The process is suspended (sleeping) until some condition becomes true. Raising a hardware interrupt, releasing a system resource the process is waiting for, or delivering a signal are examples of conditions that might wake up the process (put its state back to TASK_RUNNING) A typical example of a TASK_INTERRUPTIBLE process is a process waiting for keyboard interrupt TASK_UNINTERRUPTIBLE Like TASK_INTERRUPTIBLE, except that delivering a signal to the sleeping process leaves its state unchanged A typ