From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petri Gynther Subject: Re: [PATCH net-next v2] net: bcmgenet: collect Rx discarded packet count Date: Wed, 11 Mar 2015 10:59:32 -0700 Message-ID: References: <20150310225500.8FA34220365@puck.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: netdev , David Miller , Jaedon Shin To: Florian Fainelli Return-path: Received: from mail-qc0-f179.google.com ([209.85.216.179]:35019 "EHLO mail-qc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751274AbbCKR7d (ORCPT ); Wed, 11 Mar 2015 13:59:33 -0400 Received: by qcwr17 with SMTP id r17so12345578qcw.2 for ; Wed, 11 Mar 2015 10:59:32 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: I find the Rx discard counter very useful, as it indicates HW dropped packets, which directly affects media playback quality. In our unit tests, we actually discovered a major interrupts-off offender with this. Even with a moderate Rx traffic, we were seeing Rx discards. It turned out that using a large dmesg log buffer and dumping it with "cat /proc/kmsg" held interrupts off for long enough that bcmgenet experienced discards. It was very useful to have the discard data available when debugging this.