This message generated a parse failure. Raw output follows here. Please use 'back' to navigate. From devnull@lkml.org Mon Jun 3 11:22:30 2024 Received: from orchard.washtenaw.cc.mi.us (orchard.washtenaw.cc.mi.us [198.111.176.4]) by herbie.ucs.indiana.edu (8.6.12/8.6.12) with ESMTP id XAA28909 for ; Thu, 4 Apr 1996 23:38:00 -0500 Received: from vger.rutgers.edu by orchard.washtenaw.cc.mi.us (8.6.10/2.3) with ESMTP id XAA29884; Thu, 4 Apr 1996 23:35:40 -0500 Received: by vger.rutgers.edu id <105755-27902>; Thu, 4 Apr 1996 23:20:21 -0500 Message-Id: <31645801.7A03@central.ntua.gr> Date: Fri, 05 Apr 1996 01:15:13 +0200 From: stavrou Organization: N.T.U.A X-Mailer: Mozilla 2.01 (Win95; I) Mime-Version: 1.0 To: linux-kernel@vger.rutgers.edu Subject: Thi is a test Content-Type: multipart/mixed; boundary="------------68BC792E1664" Sender: owner-linux-kernel@vger.rutgers.edu Precedence: bulk This is a multi-part message in MIME format. --------------68BC792E1664 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit This is only a test.! By M.O.S --------------68BC792E1664 Content-Type: message/rfc822 Content-Transfer-Encoding: 7bit Content-Disposition: inline Newsgroups: linux.dev.kernel Path: news.central.ntua.gr!news.ntua.gr!swidir.switch.ch!swsbe6.switch.ch!scsing.switch.ch!news.belwue.de!news.uni-stuttgart.de!comnets.rwth-aachen.de!ratatosk.yggdrasil.com!vger.gate.yggdrasil.com!not-for-mail Approved: linux-kernel@vger.rutgers.edu References: <199604031650.CAA00695@fuzzbox.gh.cs.usyd.edu.au> X-Env-Sender: owner-linux-kernel-outgoing@vger.rutgers.edu Date: Thu, 4 Apr 1996 07:37:03 +0300 (EET DST) X-Hdr-Sender: torvalds@cs.helsinki.fi From: Linus Torvalds Subject: Re: PPP and 1.3.83 - even WORSE! Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-kernel@vger.rutgers.edu Lines: 78 On Thu, 4 Apr 1996, David Monro wrote: > > I just tried upgrading to 1.3.83, and tried a couple of transfers. On a > 14.4k link I should (and used to) get 1.5 kB/s. With 1.3.82 I get 0.9, > with 1.3.83 I get 0.23! (This is on a 68Kb file). I think we are going > to see a storm of complaints about this one ;-( That's _very_ interesting. Because 83 has only one very minimal patch to the network code, and that patch shouldn't even trigger under normal circumstances (it's only triggered when the receive queue allocation grows beyond the allowed queue length - which shouldn't happen if the sender sends sane packets within the window). Even worse, the 83 patch actually has a bug that should probably crash the machine if the new code is ever triggered ;-) I'm including the fix for this bug, but I don't think it's responsible: I really think you would see much worse problems than just bad throughput if this bug was ever triggered. I'll take a closer look at the TCP dumps soon, maybe that gives me some idea. One thing that I'm starting to suspect is simply a timing issue: the new code since 1.3.73 has been doing the ACK's from within the timer bottom half handler, asynchronously from the actual network code. Now, if there is a race within the slhc compression, it would be triggered a lot more easily thanks to the more asynchronous network behaviour. Thanks, Linus ---------- --- v1.3.83/linux/net/ipv4/tcp_input.c Wed Apr 3 16:06:57 1996 +++ linux/net/ipv4/tcp_input.c Wed Apr 3 22:00:35 1996 @@ -1487,6 +1487,7 @@ if (skb->acked) break; __skb_unlink(skb, list); + kfree_skb(skb, FREE_READ); } } @@ -1501,20 +1502,24 @@ { struct sk_buff * skb = list->next; - for (;;) { - struct sk_buff * next; + if (skb != (struct sk_buff *) list) { + for (;;) { + struct sk_buff * next; - if (skb == (struct sk_buff *) list) - break; - next = skb->next; - if (next->seq == skb->seq) { + next = skb->next; + if (next == (struct sk_buff *) list) + break; if (before(next->end_seq, skb->end_seq)) { __skb_unlink(next, list); + kfree_skb(next, FREE_READ); continue; } - __skb_unlink(skb, list); + if (next->seq == skb->seq) { + __skb_unlink(skb, list); + kfree_skb(skb, FREE_READ); + } + skb = next; } - skb = next; } } ---------- --------------68BC792E1664--