[jira] [Updated] (HADOOP-12356) CPU usage statistics on Windows

["Yunqi Zhang (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HADOOP-12356?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Yunqi Zhang updated HADOOP-12356:
---------------------------------
    Description:     (was: In {{hadoop-common/src/main/java/org/apache/hadoop/util/SysInfoWindows.java}} (in trunk), the reported CPU usage is incorrect.

{code:title=SysInfoWindows.java|borderStyle=solid}
// This is where we calculate all the usage information
void refreshIfNeeded() {
  ...
  if (lastCumCpuTimeMs != -1) {
    cpuUsage = (cumulativeCpuTimeMs - lastCumCpuTimeMs)
        / (refreshInterval * 1.0f);
  }
  ...
}
{code}

This {{cpuUsage}} is the cumulative CPU usage across all logical cores. For example, this number will range in [0.0, 12.0] if a server has 12 cores. Instead of reporting this raw number, we should do the following to be consistent with {{SysInfoLinux.java}}. In {{SysInfoLinux.java}}, {{cpuUsage}} ranges in [0.0, 1200.0], and the return value of {{getCpuUsage()}} ranges from [0.0, 100.0].

{code:title=SysInfoWindows.java|borderStyle=solid}
// This is where we calculate all the usage information
void refreshIfNeeded() {
  ...
  if (lastCumCpuTimeMs != -1) {
    cpuUsage = (cumulativeCpuTimeMs - lastCumCpuTimeMs)
        * 100F / refreshInterval;
  }
  ...
}

@Override
public float getCpuUsage() {
  refreshIfNeeded();
  return cpuUsage / numProcessors;
}
{code})

> CPU usage statistics on Windows
> -------------------------------
>
>                 Key: HADOOP-12356
>                 URL: https://issues.apache.org/jira/browse/HADOOP-12356
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: util
>         Environment: CPU: Intel Xeon
> OS: Windows server
>            Reporter: Yunqi Zhang
>              Labels: easyfix, newbie
>   Original Estimate: 2h
>  Remaining Estimate: 2h
>




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