From mboxrd@z Thu Jan 1 00:00:00 1970 From: TB Subject: Re: [PATCH] tcp_cubic: limit delayed_ack ratio to prevent divide error Date: Fri, 06 May 2011 12:15:46 -0400 Message-ID: <4DC41EB2.6070404@techboom.com> References: <20110504113351.4643a0c9@nehalam> <16668.1304537481@localhost> <20110504123738.7bb4d1ee@nehalam> <20110504.124053.260068550.davem@davemloft.net> <20110504130456.425dee68@nehalam> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Stephen Hemminger , David Miller , Sangtae Ha , Injong Rhee , "Valdis.Kletnieks@vt.edu" , "rdunlap@xenotime.net" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" To: "Brandeburg, Jesse" Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org -----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 > > 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 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJNxB6yAAoJENOh8x1aI8Ye4ocH/3+6gjWWppgOwql0J4XGGD5R wJX+u8A+YK2V+GBvxFgQs/qNa3IB/nnWwELolflO80twq2JrOq1I6g2n1VJhHjX4 b5jyROMe2gPHRKESibi84gNIuoImq4bqM/S1u7xWzcikTh8FxCevYQXTNilIKOOf siuOIypFY7AyqSPjhq5/+HpTrrOQa097PAcVAr8RBO7niyrxAE75ACTolGAKBfvQ HlOYKmxBT8SbnZ7YJNINopPdtpqz3iaraKWUoT44Wuv8Q8jt0cqB7YJWl0RG/C3y ABK50Qihl1p6M+LL9jjR2YwVFkjiLyN3fO8g2pjVfn4wh0afFCyWtitN0OFd/4I= =Vy5E -----END PGP SIGNATURE-----