这里最后面的数字’2’表示的是采样周期,Linux下有很多命令支持这样的参数,像sar/iostat/vmstat/mpstat等,很多资料是给的例子是用1,但在实践的过程中发现,用1的结果常常波动比较大,不稳定,所以在具体的实践中,笔者推荐用2或者更大一些的值,获得的结果相对稳定一些。 关于CPU,有下面一些经验可供参考: Run Queue:...
5.2 Kernel Memory Paging 内存分页在正常情况下总是活跃的,与memory swapping(译注:内存交换)之间不要搞错了.内存分页是指内核会定期将内存中的数据同步到硬盘,这个过程就是Memory Paging.日复一日,应用最终将会消耗掉所有的内存空间.考虑到这点,内核就必须经常扫描内存空间并且收回其中未被使用的内存页,然后再重新...
多数现代处理器都能够运行一个进程(单一线程)或者线程.多路超线程处理器有能力运行多个线程.然而,Linux 内核还是把每个处理器核心的双核心芯片作为独立的处理器.比如,以Linux 内核的系统在一个双核心处理器上,是报告显示为两个独立的处理器. 一个标准的Linux 内核可以运行50 至 50,000 的处理线程.在只有一个CPU时...
iotop是一个检测Linux系统进程IO的工具,界面类似top,如下图。 [xgj@entel2 ~]$ iotopNetlink error: Operation not permitted (1)The Linux kernel interfaces that iotop relies on now require root privilegesor the NET_ADMIN capability. This change occurred because a security issue(CVE-2011-2494) was ...
Linux System and Performance Monitoring(CPU篇) Date: 2009.07.21 Author: Darren Hoch 译: Tonnyom[AT]hotmail.com 2009.08.10 前言: 网上其实有很多关于这方面的文章,那为什么还会有此篇呢,有这么几个原因,是我翻译的动力,第一,概念和内容虽然老套,但都讲得很透彻,而且还很全面.第二,理论结合实际,其中案例...
Linux Performance Analysis in 60,000 Milliseconds 显示了调查中使用的前十个命令(视频, PDF)。由我本人和 Netflix 的性能工程团队撰写(2015 年)。 My post Performance Tuning Linux Instances on EC2 includes the tunables we're using at Netflix (2015). ...
In the previous chapter, we looked at Oracle performance monitoring tools. However, performance problems often occur outside the Oracle environment at the processor and memory, network, or storage level. It is therefore important to understand the information provided, not only by the Oracle ...
Among others, Linux provides a performance monitoring and analysis tool called convenientlyperf. So what distinguishesperffrom other well-known tools with which you are already familiar? The answer is thatperfprovides access to thePerformance Monitoring Unitin the CPU, and thus allows us to have a...
Ifvmstatandiostatcommands are not available in your Linux machine, please install thesysstatpackage. Thevmstat,sar,andiostatcommands are the collection of package included insysstat – the system monitoring tools. You may download and installsysstatusing the source tarball from linksysstat, but we rec...
As we discussed in ourLinux performance monitoring introductionarticle, measuring IO subsystem performance is very important. If someone is complaining that a database (or any application) running on one server (with certain filesystem, or RAID configuration) is running faster than the same database...