The following reply was made to PR kern/31430; it has been noted by GNATS.

From: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
To: simonb@wasabisystems.com
Cc: christos@netbsd.org, gnats-bugs@netbsd.org,
	kern-bug-people@netbsd.org, gnats-admin@netbsd.org,
	netbsd-bugs@netbsd.org
Subject: Re: kern/31430: ptyfs isn't getting mtime right 
Date: Thu, 13 Oct 2005 01:00:50 +0900

 > The patch below is a result of a discussion off-line with Christos.
 > The granularity of the mtime doesn't need to be down to the nanosecond
 > - using the kernel "time" variable (which is updated on each
 > hardclock call) saves a potentially relatively expensive call to
 > microtime/nanotime for each write, and is more than accurate enough to
 > track pty idle times.
 
 it isn't good to mix "time" and nanotime
 because it can make timestamps go backward sometimes.
 
 YAMAMOTO Takashi