From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH 17/20][BNX2]: Enhance the heartbeat. Date: Wed, 02 May 2007 03:38:53 -0400 Message-ID: <4638400D.5010306@garzik.org> References: <1178068656.4820.53.camel@dell> <46383B00.4080605@garzik.org> <20070502.002426.38687430.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: mchan@broadcom.com, netdev@vger.kernel.org To: David Miller Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:56195 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751922AbXEBHjV (ORCPT ); Wed, 2 May 2007 03:39:21 -0400 In-Reply-To: <20070502.002426.38687430.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org David Miller wrote: > From: Jeff Garzik > Date: Wed, 02 May 2007 03:17:20 -0400 > >> Michael Chan wrote: >>> [BNX2]: Enhance the heartbeat. >>> >>> In addition to the periodic heartbeat, we're adding a heartbeat >>> request interrupt when the heartbeat is late. This is useful >>> especially in -rt kernels where the timer frequently runs late. >>> >>> Signed-off-by: Michael Chan >> Should we really be adding code for such a special situation to upstream >> code? >> >> I lean towards "no", but defer to your and DaveM's judgement here. > > My understanding of this situation is that if the timer is delayed a > lot, which can happen with the -rt kernel, we don't send the heartbeat > ping to the chip within the required margin. > > If the margin is not met, the ASF firmware takes this as a signal that > the host system is down, and does things like reset the network card > and other things we don't want it to do. Thanks for the explanation. My main concern was * adding code to use a kernel facility * then, adding code to handle when that kernel facility doesn't work and also * adding code for a situation that never occurs in the upstream kernel. Regards, Jeff