From: Stephen Hemminger <shemminger@vyatta.com>
To: TB <lkml@techboom.com>
Cc: "Brandeburg, Jesse" <jesse.brandeburg@intel.com>,
David Miller <davem@davemloft.net>,
Sangtae Ha <sangtae.ha@gmail.com>,
Injong Rhee <injongrhee@gmail.com>,
"Valdis.Kletnieks@vt.edu" <Valdis.Kletnieks@vt.edu>,
"rdunlap@xenotime.net" <rdunlap@xenotime.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tcp_cubic: limit delayed_ack ratio to prevent divide error
Date: Fri, 6 May 2011 09:53:59 -0700 [thread overview]
Message-ID: <20110506095359.57c4fb38@nehalam> (raw)
In-Reply-To: <4DC41EB2.6070404@techboom.com>
On Fri, 06 May 2011 12:15:46 -0400
TB <lkml@techboom.com> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On 11-05-04 04:53 PM, Brandeburg, Jesse wrote:
> >
> >
> > On Wed, 4 May 2011, Stephen Hemminger wrote:
> >
> >> TCP Cubic keeps a metric that estimates the amount of delayed
> >> acknowledgements to use in adjusting the window. If an abnormally
> >> large number of packets are acknowledged at once, then the update
> >> could wrap and reach zero. This kind of ACK could only
> >> happen when there was a large window and huge number of
> >> ACK's were lost.
> >>
> >> This patch limits the value of delayed ack ratio. The choice of 32
> >> is just a conservative value since normally it should be range of
> >> 1 to 4 packets.
> >>
> >> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> >
> > patch seems fine, but please credit the reporter (lkml@techboom.com) with
> > reporting the issue with logs, maybe even with Reported-by: and some kind
> > of reference to the panic message or the email thread in the text or
> > header?
>
> We're currently testing the patch on 6 production servers
Thank you, is there some regularity to the failures previously?
next prev parent reply other threads:[~2011-05-06 16:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4DC178D3.6030308@techboom.com>
2011-05-04 17:49 ` Divide error in bictcp_cong_avoid ? Randy Dunlap
2011-05-04 18:33 ` Stephen Hemminger
2011-05-04 18:35 ` Randy Dunlap
2011-05-04 19:03 ` TB
2011-05-04 18:56 ` David Miller
2011-05-04 19:31 ` Valdis.Kletnieks
2011-05-04 19:37 ` Stephen Hemminger
2011-05-04 19:40 ` David Miller
2011-05-04 20:01 ` Valdis.Kletnieks
2011-05-04 20:04 ` [PATCH] tcp_cubic: limit delayed_ack ratio to prevent divide error Stephen Hemminger
2011-05-04 20:53 ` Brandeburg, Jesse
2011-05-06 16:15 ` TB
2011-05-06 16:53 ` Stephen Hemminger [this message]
2011-05-06 17:39 ` TB
2011-05-11 14:49 ` TB
2011-05-11 15:22 ` Stephen Hemminger
2011-05-11 15:35 ` TB
2011-05-08 22:52 ` David Miller
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