From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH 1/2] igb: Implement reading of reg RQDPC (Receive Queue Drop Packet Count) Date: Thu, 7 May 2009 12:24:28 -0700 Message-ID: <20090507122428.0a8e3309@nehalam> References: <1241703346.18487.22.camel@localhost.localdomain> <1241703431.18487.25.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: "Williams, Mitch A" , Jesper Dangaard Brouer , "Kirsher, Jeffrey T" , "David S. Miller" , "netdev@vger.kernel.org" , "e1000-devel@lists.sourceforge.net" , "Ronciak, John" , "Waskiewicz Jr, Peter P" To: Jesper Dangaard Brouer Return-path: Received: from mail.vyatta.com ([76.74.103.46]:50239 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751308AbZEGTYe (ORCPT ); Thu, 7 May 2009 15:24:34 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 7 May 2009 21:19:35 +0200 (CEST) Jesper Dangaard Brouer wrote: > > On Thu, 7 May 2009, Williams, Mitch A wrote: > > >> Implement reading the per queue drop stats register > >> RQDPC (Receive Queue Drop Packet Count). It counts the number of > >> packets dropped by a queue due to lack of descriptors available. > >> > >> Notice RQDPC (Receive Queue Drop Packet Count) stats only gets > >> incremented, if the DROP_EN bit it set (in the SRRCTL register > >> for that queue). If DROP_EN bit is NOT set, then the some what > >> equivalent count is stored in RNBC (not per queue basis). > >> > >> The RQDPC register is only 12 bit, thus the precision might > >> suffer due to overrun in-between the watchdog polling interval. > > > > NAK. 82575 doesn't have RQDPC registers. You need to check > > which part you're running on before you read those registers. > > Strange, I though the RQDPC register were compatible with the 82575 > registers, as the 82576 datasheet states: > > Quote 82576 DS: > Note: In order to keep compatibility with the 82575, for queues 0-3, > these registers are aliased to addresses 0x2830, 0x2930, 0x2A30 & 0x2B30 > respectively. > > And I do take care of reading the aliased adresses in the RQDPC define > statement for queues 0-3. > > Well, I unfortunatly done have a 82575 based NIC anymore (as my prototype > NIC from Hotlava Systems Inc. just died). And I don't have the 82575 > datasheet, it does not seem to be available!? > > Any chance I could get the 82575 register datasheet? > > > > Other than that, this looks OK to me. > > That sounds good :-) > > ps. It will be monday or tuesday before I have time to repost the > patchset. > > Cheers, > Jesper Brouer > I'll test the patch, but what would happen if the registers were not there?