From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: Netchannles: first stage has been completed. Further ideas. Date: Fri, 28 Jul 2006 09:47:05 +0400 Message-ID: <20060728054704.GD11210@2ka.mipt.ru> References: <20060727165121.GA6637@2ka.mipt.ru> <20060727205651.GA29953@ms2.inr.ac.ru> <20060728051723.GA11210@2ka.mipt.ru> <20060727.223400.97292695.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Cc: kuznet@ms2.inr.ac.ru, rusty@rustcorp.com.au, netdev@vger.kernel.org Return-path: Received: from relay.2ka.mipt.ru ([194.85.82.65]:8120 "EHLO 2ka.mipt.ru") by vger.kernel.org with ESMTP id S1751975AbWG1Fr2 (ORCPT ); Fri, 28 Jul 2006 01:47:28 -0400 To: David Miller Content-Disposition: inline In-Reply-To: <20060727.223400.97292695.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Jul 27, 2006 at 10:34:00PM -0700, David Miller (davem@davemloft.net) wrote: > From: Evgeniy Polyakov > Date: Fri, 28 Jul 2006 09:17:25 +0400 > > > What would you expect from non-preemptible kernel? Hard lockup, no acks, > > no soft irqs. > > Why does pressing Ctrl-Z on the user process stop kernel soft irq > processing? I do not know, why Alexey decided that Ctrl-Z was ever pressed. I'm saying about the case when keventd ate 100% of CPU, but stack worked with (very) long delays. Obviously userspace was unresponsible and no data arrived there. It is an analogy that posponed softirq work does not destroy connections as long as process context protocol processing with delays. User does not get it's data, so no need to send an ack. And if it is impossible to get that data at all, user should not care that sending side does not see acks. When user is capable to get that data, it starts to acknowledge. -- Evgeniy Polyakov