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Date:      Sat, 14 Dec 2013 23:20:42 +0100
From:      Marc UBM <ubm.freebsd@googlemail.com>
To:        freebsd-current@freebsd.org
Subject:   Re: SVN commit 259045 breaks -CURRENT
Message-ID:  <20131214232042.dbf77b9d6227c38292def34a@gmail.com>
In-Reply-To: <20131214215904.GA24545@troutmask.apl.washington.edu>
References:  <52ACD12A.5020906@freebsd.org> <20131214215904.GA24545@troutmask.apl.washington.edu>

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On Sat, 14 Dec 2013 13:59:04 -0800
Steve Kargl <sgk@troutmask.apl.washington.edu> wrote:

> On Sat, Dec 14, 2013 at 10:44:10PM +0100, Stefan Esser wrote:
> > I noticed a severe slowdown and network problems on my amd64 -CURRENT
> > system. By bisecting SVN revisions I identified the following commit
> > to be responsible:
> > 
> > ----------------------------------------------------------------------
> > r259045 | kib | 2013-12-06 22:44:13 +0100 (Fri, 06 Dec 2013) | 9 lines
> > 
> > Disallow optimizations which potentially remove boundary checks
> > for signed values due to a compiler authors considering integer
> > overflow as impossible.
> > 
> > The change follows suit of other projects taking the same measure.
> > ----------------------------------------------------------------------
> > 
> > This commit added the following line to /sys/conf/kern.mk:
> > 
> > CFLAGS+=       -fno-strict-overflow
> > 
> > 
> > The most obvious symptoms of the problem on my system are:
> > 
> > 1) sa-spamd needs > 140 seconds to start
> >    (instead of a few seconds)
> > 
> > 2) SSH logins are very slow, many seconds of delay between connect
> >    and password prompt, several seconds after password entry until
> >    a command prompt appears (normally instantaneous)
> > 
> 
> Ah, so that explains the behavior I'm see.  Just updated a circa Aug 3rd
> i386 FreeBSD to top-of-tree.  My ssh logins to my work system take 30+
> seconds now. :(

I observe dnsmasq causing extremely high network latency without any
visible reason - though that may not be related. I'll remove
-fno-strict-overflow, recompile kernel and see if anything changes.

Bye
Marc



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