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=ham 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 1F9CAC432C3 for ; Sat, 16 Nov 2019 15:57:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7EAA21479 for ; Sat, 16 Nov 2019 15:57:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919849; bh=U/6tRCUAgN7vLtq1CMV91hKOfrocRssLaPKmD5mtqa4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qNxCIzGXzO/+zAK1q3WX5L+bkRj8xxBJ8pfgF8tSMsAhaQKRhFH7qBhWuW6ooOdmK Pmj0Q5TKOdx7Y8IEnB8TxbUO8jDxNTaHdHloVp6x1Z8yBIi0Hh0s3SXipsF0XTQb8M FZEEN9qVExYS3Huo+sXpH43Vr/WQpOTsEA8EA7Wk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730874AbfKPP52 (ORCPT ); Sat, 16 Nov 2019 10:57:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:37052 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731533AbfKPPzJ (ORCPT ); Sat, 16 Nov 2019 10:55:09 -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 C0ABB2186D; Sat, 16 Nov 2019 15:55:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919709; bh=U/6tRCUAgN7vLtq1CMV91hKOfrocRssLaPKmD5mtqa4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SwFeVxkzGTf2iOygAThV7TjwKE47Zg+tH7tRE8RO+4muIFsqRhSiJOQ/qCLXKddo2 f6/QWV+pAdicqENlSHTqwZyKtb5ZENoaluDUW2VjKHBB2EU+VKNI5qgWaWjZAo2/Mb STmj8i0riVYD3n2A4MzmtKmdQud9PwJhRKmO4CGs= 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 4.4 53/77] igb: shorten maximum PHC timecounter update interval Date: Sat, 16 Nov 2019 10:53:15 -0500 Message-Id: <20191116155339.11909-53-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116155339.11909-1-sashal@kernel.org> References: <20191116155339.11909-1-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 c44df87c38de2..5e65d8a78c3ed 100644 --- a/drivers/net/ethernet/intel/igb/igb_ptp.c +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c @@ -65,9 +65,15 @@ * * 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 (1 << E1000_TIMINCA_16NS_SHIFT) #define INCVALUE_82576_MASK ((1 << E1000_TIMINCA_16NS_SHIFT) - 1) -- 2.20.1