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 Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9DB9ACA0EE9 for ; Tue, 19 Aug 2025 06:09:35 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 537C160839; Tue, 19 Aug 2025 06:09:35 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id XGid9AJHR4ER; Tue, 19 Aug 2025 06:09:34 +0000 (UTC) X-Comment: SPF check N/A for local connections - client-ip=140.211.166.142; helo=lists1.osuosl.org; envelope-from=intel-wired-lan-bounces@osuosl.org; receiver= DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org BF9826083B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osuosl.org; s=default; t=1755583774; bh=rL+TrUW6tiyvddHWQRgJrjB30uAutfdbI4yIw0BN8hQ=; h=From:To:Cc:In-Reply-To:References:Date:Subject:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=b7KAtlcDG08LbcK8WA9L8PLPKCNWsGO4hsZ2Vlht8JTDDw9Qu5iXOc3wwpeMJvukn zD8Qs3G/xadrAZfl/pjkcexyHVXTW7YjC1V1xU7de7NG0mMtY/AURLW7SH98Gcm/kB v/b2ljP0tSl53U63DwiyunA9ptbUhfIBAQk08rRPzPB40Qgp+MGJRnILpn2fACS9Ik X5z5QBsmTbzklHolt6Zh/wqXrribpxy01fzX/UU0YZD1o/TtvJh7q0sV2YkWUX00Ix HLDQDTP0e+k9Hh6mbnnvismv6CymJAkf5kW+JiG5WB79/l4+kamZKJ5v5tuTM3nJgt 61ENWRSzsfebQ== Received: from lists1.osuosl.org (lists1.osuosl.org [140.211.166.142]) by smtp3.osuosl.org (Postfix) with ESMTP id BF9826083B; Tue, 19 Aug 2025 06:09:34 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists1.osuosl.org (Postfix) with ESMTP id 238A9DE6 for ; Tue, 19 Aug 2025 06:09:33 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 01B416083A for ; Tue, 19 Aug 2025 06:09:33 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id f0aqwD9XD4FV for ; Tue, 19 Aug 2025 06:09:32 +0000 (UTC) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=2a0a:51c0:0:12e:550::1; helo=galois.linutronix.de; envelope-from=kurt@linutronix.de; receiver= DMARC-Filter: OpenDMARC Filter v1.4.2 smtp3.osuosl.org 02F1760837 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org 02F1760837 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by smtp3.osuosl.org (Postfix) with ESMTPS id 02F1760837 for ; Tue, 19 Aug 2025 06:09:31 +0000 (UTC) From: Kurt Kanzenbach To: Miroslav Lichvar Cc: Tony Nguyen , Przemek Kitszel , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Richard Cochran , Vinicius Costa Gomes , Sebastian Andrzej Siewior , intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org In-Reply-To: References: <20250815-igb_irq_ts-v1-1-8c6fc0353422@linutronix.de> Date: Tue, 19 Aug 2025 08:09:25 +0200 Message-ID: <87y0rf4zca.fsf@jax.kurt.home> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1755583766; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rL+TrUW6tiyvddHWQRgJrjB30uAutfdbI4yIw0BN8hQ=; b=ZGCq7qCfzC5H3GygyPZRbiTCwyFLWcjdY2GuCVTSeKzsFHLFi7TnN2rA4bRkAEQYHEWwx2 Sfa9Xe29n0OaffTVuC9J6MUc67waFR1yW/pkPD6SAYohfACHVFENHKtoFJUj3Tw1jwJWC0 8AYmBdbwddYzJ0w6lzjwNX07k/tMJrnsyulDzM8WbTMqCmUXTihkn+dQK6hLAb8sZ9V3Ax lVnVn14sqyaxE+72Iw7hO6am1JCWDyRrJdihxn8jcTxYsCZm0sf5bWue+IFqtBvic41CgV ChDG7IP/Ijw6260Hi/ammf/N/MVPo9J3DnLZTDrsaosc892S5+FbG5nupgmt9g== X-Mailman-Original-DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1755583766; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rL+TrUW6tiyvddHWQRgJrjB30uAutfdbI4yIw0BN8hQ=; b=SdkPN5lASqNdoU8R88W/4y657SDrKUFPVaiX6qrGSBu6g8zZKUVSj7+sEnbKFPZte733Tl zP6HS2zQ2xQOF9Ag== X-Mailman-Original-Authentication-Results: smtp3.osuosl.org; dmarc=pass (p=none dis=none) header.from=linutronix.de X-Mailman-Original-Authentication-Results: smtp3.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=ZGCq7qCf; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=SdkPN5lA Subject: Re: [Intel-wired-lan] [PATCH iwl-next] igb: Retrieve Tx timestamp directly from interrupt X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Mon Aug 18 2025, Miroslav Lichvar wrote: > On Fri, Aug 15, 2025 at 08:50:23AM +0200, Kurt Kanzenbach wrote: >> Retrieve Tx timestamp directly from interrupt handler. >>=20 >> The current implementation uses schedule_work() which is executed by the >> system work queue to retrieve Tx timestamps. This increases latency and = can >> lead to timeouts in case of heavy system load. >>=20 >> Therefore, fetch the timestamp directly from the interrupt handler. >>=20 >> The work queue code stays for the Intel 82576. Tested on Intel i210. > > I tested this patch on 6.17-rc1 with an Intel I350 card on a NTP > server (chrony 4.4), measuring packet rates and TX timestamp accuracy > with ntpperf. While the HW TX timestamping seems more reliable at some > lower request rates, there seems to be about 40% drop in the overall > performance of the server in how much requests it can handle (falling > back to SW timestamps when HW timestamp is missed). Is this expected > or something to be considered?=20 Thanks for testing! Nope, this is not really expected. Let me see if I can reproduce your results and see where that comes from. 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