[jira] [Commented] (IGNITE-13015) Use nano time in node failure detection.

["Ivan Daschinskiy (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-13015?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17108348#comment-17108348 ] 

Ivan Daschinskiy commented on IGNITE-13015:
-------------------------------------------

Huge +1. {{System.currentTimeMillis()}} is backed by {{gettimeofday()}} and is not monotonic. Instead, {{System.nanoTime()}}, that is backed by {{clock_gettime(CLOCK_MONOTONIC,..)}} has monotonic guarantee with nanoseconds precision. Moreover, both methods are not system calls in modern Linuxes thanks to vDSO, so we can avoid context switches and don't worry about performance drop. (see [here|http://man7.org/linux/man-pages/man7/vdso.7.html] for details). 

> Use nano time in node failure detection.
> ----------------------------------------
>
>                 Key: IGNITE-13015
>                 URL: https://issues.apache.org/jira/browse/IGNITE-13015
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Vladimir Steshin
>            Assignee: Vladimir Steshin
>            Priority: Minor
>              Labels: iep-45
>
> Make sure in node failure detection not used:
> {code:java}
> System.currentTimeMillis()
> and
> IgniteUtils.currentTimeMillis()
> {code}
> Disadventages:
> 1)	Current system time has no quarantine of strict forward movement. System time can be adjusted, synchronized by NTP as example. This can lead to incorrect and negative delays.
> 2)	 IgniteUtils.currentTimeMillis() is granulated by 10ms



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