From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22BD5C432C3 for ; Sat, 16 Nov 2019 16:19:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECDFF214DE for ; Sat, 16 Nov 2019 16:19:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573921189; bh=IX6ejNhOzqzCr1fBgCEaKvxLcJCK6m+OsCxX9zF9tQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=c50VvLESeQMqfd+Lbr6wCTiVc3lIivHYGx1ToRpFFrshKTF5twIQPILXtv0Pi0zJR HihJlrTq7ArugMojjxZk9IfYHJ9ErIBvpnNSCT07aGNmFAdYB8K25zcofBUGaWzYY/ 7lXVq4ivF09xZ2iEKBif7xuVeDIpN6ZEs2eQMHcM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729254AbfKPPp4 (ORCPT ); Sat, 16 Nov 2019 10:45:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:51874 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728488AbfKPPpx (ORCPT ); Sat, 16 Nov 2019 10:45:53 -0500 Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7198920857; Sat, 16 Nov 2019 15:45:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919153; bh=IX6ejNhOzqzCr1fBgCEaKvxLcJCK6m+OsCxX9zF9tQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pXv7DaEQ/db2b0Np8a9HAYPwkfxOh3XQAp9GQu/ISPcJTy4j1AZZmZEmNGOOv1WMF DaN3Zm0KjL42r6kuHaCz7TGf/rGSgv4UlkEleyY48j4Qh9Y317AJQ/iKgRSPE9qCMv vaGR3Ie1xCmgPp/IRxlrDrsx7z1IedDHzRdwRMPQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Miroslav Lichvar , Jacob Keller , Richard Cochran , Thomas Gleixner , Aaron Brown , Jeff Kirsher , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 166/237] igb: shorten maximum PHC timecounter update interval Date: Sat, 16 Nov 2019 10:40:01 -0500 Message-Id: <20191116154113.7417-166-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116154113.7417-1-sashal@kernel.org> References: <20191116154113.7417-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Miroslav Lichvar [ Upstream commit 094bf4d0e9657f6ea1ee3d7e07ce3970796949ce ] The timecounter needs to be updated at least once per ~550 seconds in order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old timestamp. Since commit 500462a9d ("timers: Switch to a non-cascading wheel"), scheduling of delayed work seems to be less accurate and a requested delay of 540 seconds may actually be longer than 550 seconds. Shorten the delay to 480 seconds to be sure the timecounter is updated in time. This fixes an issue with HW timestamps on 82580/I350/I354 being off by ~1100 seconds for few seconds every ~9 minutes. Cc: Jacob Keller Cc: Richard Cochran Cc: Thomas Gleixner Signed-off-by: Miroslav Lichvar Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/igb/igb_ptp.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c index 9f4d700e09df3..29ced6b74d364 100644 --- a/drivers/net/ethernet/intel/igb/igb_ptp.c +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c @@ -51,9 +51,15 @@ * * The 40 bit 82580 SYSTIM overflows every * 2^40 * 10^-9 / 60 = 18.3 minutes. + * + * SYSTIM is converted to real time using a timecounter. As + * timecounter_cyc2time() allows old timestamps, the timecounter + * needs to be updated at least once per half of the SYSTIM interval. + * Scheduling of delayed work is not very accurate, so we aim for 8 + * minutes to be sure the actual interval is shorter than 9.16 minutes. */ -#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 9) +#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 8) #define IGB_PTP_TX_TIMEOUT (HZ * 15) #define INCPERIOD_82576 BIT(E1000_TIMINCA_16NS_SHIFT) #define INCVALUE_82576_MASK GENMASK(E1000_TIMINCA_16NS_SHIFT - 1, 0) -- 2.20.1