From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: [PATCH net-next 5/5] ethtool: Note common alternate exit condition for interrupt coalescing Date: Tue, 16 Aug 2011 01:09:22 +0100 Message-ID: <1313453362.2731.61.camel@bwh-desktop> References: <1313453180.2731.57.camel@bwh-desktop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Eli Cohen To: David Miller Return-path: Received: from exchange.solarflare.com ([216.237.3.220]:41192 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753133Ab1HPAJZ (ORCPT ); Mon, 15 Aug 2011 20:09:25 -0400 In-Reply-To: <1313453180.2731.57.camel@bwh-desktop> Sender: netdev-owner@vger.kernel.org List-ID: Many implementations ignore the value of max_frames and do not treat usecs == 0 as special. Document this as deprecated. Signed-off-by: Ben Hutchings --- include/linux/ethtool.h | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 42378b3..3829712 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h @@ -173,6 +173,12 @@ struct ethtool_eeprom { * would cause interrupts to never be generated. To disable * coalescing, set usecs = 0 and max_frames = 1. * + * Some implementations ignore the value of max_frames and use the + * condition: + * time_since_first_completion >= usecs + * This is deprecated. Drivers for hardware that does not support + * counting completions should validate that max_frames == !rx_usecs. + * * Adaptive RX/TX coalescing is an algorithm implemented by some * drivers to improve latency under low packet rates and improve * throughput under high packet rates. Some drivers only implement -- 1.7.4.4 -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.