From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: why this behavior in 3.16 kernel ? Date: Wed, 03 Aug 2016 12:48:49 -0500 Message-ID: <877fbxhhfi.fsf@x220.int.ebiederm.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: (cool linux's message of "Wed, 3 Aug 2016 16:38:25 +0530") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: cool linux Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: containers.vger.kernel.org cool linux writes: > Hi, > > I have executed below script on 3.16 kernel and it took to finish almost > 1.30sec to 2 minutes, where as in my older kernel(3.2.30) it took only 3 > secs. > > ================================================ > date > > for (( i=1; i <= 2000; i++ )) > do > ip netns exec gmk ip link show > /dev/null > done > > date > ================================================ > > Please guide me why this behavior in 3.16 kernel ? Good question. What happens on a modern kernel? 4.7 is the most recent release, 3.16 was released two years ago. My hunch is that you just started using systemd and it has changed the defaults with all of the mounts. But shrug. I don't recall how all of those relevant kernel pieces operated two years ago. Eric