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 smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 956EEEB7EB5 for ; Wed, 4 Mar 2026 09:35:20 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 5CE684083C; Wed, 4 Mar 2026 09:35:20 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id OEMo2ZsmPX87; Wed, 4 Mar 2026 09:35:18 +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 smtp4.osuosl.org 2D71F40801 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osuosl.org; s=default; t=1772616918; bh=34x8dW+VODfI2RuFdRgreGOgi0nhsq6qAyMMwtOtc+0=; h=Date:From:To:Cc:References:In-Reply-To:Subject:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=mNjS1VReZjy5k8ImYHnB8HZTDuAprzCXwOPdG4+T8kESsCc3h6ueGW1jfA7D5lVm1 C1N9ZSH2edKSXTEbTByqhMZS6RJqmwf+t3qT38IC5QhrdRnPWvuryGqsvKr8HX+5Az D6WNLufZSo93V9tqnSLJWCbPx9K0B6GWY35BSeq6ee3LavO5yI59HAgw4m91qsNfWD GyXQzdlyd9lgmWawmnjdp3YpNMMvivZchn4pPzAUD7+++WSOaKXjPgHYnHUUFYEC7F mHwwGcXkxGWf3lzAUx0S/9VXWrnQrl0hdC6R8KeGa0D3xF5rj29bRb7S2N81n71DnV SymLEMJ32oAOw== Received: from lists1.osuosl.org (lists1.osuosl.org [140.211.166.142]) by smtp4.osuosl.org (Postfix) with ESMTP id 2D71F40801; Wed, 4 Mar 2026 09:35:18 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists1.osuosl.org (Postfix) with ESMTP id 7C0C11EB for ; Wed, 4 Mar 2026 09:35:17 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 6DC8D403AB for ; Wed, 4 Mar 2026 09:35:17 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id MfzSk34RHQMb for ; Wed, 4 Mar 2026 09:35:16 +0000 (UTC) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=170.10.133.124; helo=us-smtp-delivery-124.mimecast.com; envelope-from=mlichvar@redhat.com; receiver= DMARC-Filter: OpenDMARC Filter v1.4.2 smtp2.osuosl.org 424E14023D DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 424E14023D Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by smtp2.osuosl.org (Postfix) with ESMTPS id 424E14023D for ; Wed, 4 Mar 2026 09:35:15 +0000 (UTC) Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-224-Px0G-HPoO3GdBTa0AchyCA-1; Wed, 04 Mar 2026 04:35:11 -0500 X-MC-Unique: Px0G-HPoO3GdBTa0AchyCA-1 X-Mimecast-MFC-AGG-ID: Px0G-HPoO3GdBTa0AchyCA_1772616909 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 567131800365; Wed, 4 Mar 2026 09:35:08 +0000 (UTC) Received: from localhost (unknown [10.43.135.229]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5086D180075F; Wed, 4 Mar 2026 09:35:03 +0000 (UTC) Date: Wed, 4 Mar 2026 10:35:01 +0100 From: Miroslav Lichvar To: Kurt Kanzenbach Cc: Paul Menzel , Tony Nguyen , Przemek Kitszel , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Richard Cochran , Vinicius Costa Gomes , Sebastian Andrzej Siewior , Vadim Fedorenko , Jacob Keller , intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: References: <20260303-igb_irq_ts-v4-1-cbae7f127061@linutronix.de> <9805389e-9ea4-4e7a-a122-65f733ead33c@molgen.mpg.de> <87qzq1rq2k.fsf@jax.kurt.home> MIME-Version: 1.0 In-Reply-To: <87qzq1rq2k.fsf@jax.kurt.home> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-MFC-PROC-ID: Yqfhu3rXSIPL_UpvLpn4bI_23XJdy6ZEfpvdy-dsQWE_1772616909 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772616914; 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=34x8dW+VODfI2RuFdRgreGOgi0nhsq6qAyMMwtOtc+0=; b=YDAClWq+16IWSAKh78s7HZ4PU60xbv1sLURKcV3zHwX6fvgKg7OxRRwCt91c/vDczYGIXO HstQ1coAwP1rFUAFdXjbhI0Y3ASVMkYT2d+dYSThauUKb7713Wx3NQa1BQjbxnfnHmCIj5 e9BHMmQeRgKpSLKQE5JOUPhNqXCccH0= X-Mailman-Original-Authentication-Results: smtp2.osuosl.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com X-Mailman-Original-Authentication-Results: smtp2.osuosl.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=YDAClWq+ Subject: Re: [Intel-wired-lan] [PATCH iwl-next v4] igb: Retrieve Tx timestamp from BH workqueue 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" On Tue, Mar 03, 2026 at 02:38:11PM +0100, Kurt Kanzenbach wrote: > > It would be great, if you shared the numbers. Did Miroslav already test > > this? > > Great question. I did test with ptp4l and synchronization looks fine < > below 10ns back to back as expected. I did not test with ntpperf, > because I was never able to reproduce the NTP regression to the same > extent as Miroslav reported. Therefore, Miroslav is on Cc in case he > wants to test it. Let's see. I ran the same test with I350 as before and there still seems to be a regression, but interestingly it's quite different to the previous versions of the patch. It's like there is a load-sensitive on/off switch. Without the patch: | responses | response time (ns) rate clients | lost invalid basic xleave | min mean max stddev 150000 15000 0.00% 0.00% 0.00% 100.00% +4188 +36475 +193328 16179 157500 15750 0.02% 0.00% 0.02% 99.96% +6373 +42969 +683894 22682 165375 16384 0.03% 0.00% 0.00% 99.97% +7911 +43960 +692471 24454 173643 16384 0.06% 0.00% 0.00% 99.94% +8323 +45627 +707240 28452 182325 16384 0.06% 0.00% 0.00% 99.94% +8404 +47292 +722524 26936 191441 16384 0.00% 0.00% 0.00% 100.00% +8930 +51738 +223727 14272 201013 16384 0.05% 0.00% 0.00% 99.95% +9634 +53696 +776445 23783 211063 16384 0.00% 0.00% 0.00% 100.00% +14393 +54558 +329546 20473 221616 16384 2.59% 0.00% 0.05% 97.36% +23924 +321205 +518192 21838 232696 16384 7.00% 0.00% 0.10% 92.90% +33396 +337709 +575661 21017 244330 16384 10.82% 0.00% 0.15% 89.03% +34188 +340248 +556237 20880 With the patch: 150000 15000 5.11% 0.00% 0.00% 94.88% +4426 +460642 +640884 83746 157500 15750 11.54% 0.00% 0.26% 88.20% +14434 +543656 +738355 30349 165375 16384 15.61% 0.00% 0.31% 84.08% +35822 +515304 +833859 25596 173643 16384 19.58% 0.00% 0.37% 80.05% +20762 +568962 +900100 28118 182325 16384 23.46% 0.00% 0.42% 76.13% +41829 +547974 +804170 27890 191441 16384 27.23% 0.00% 0.46% 72.31% +15182 +557920 +798212 28868 201013 16384 30.51% 0.00% 0.49% 69.00% +15980 +560764 +805576 29979 211063 16384 0.06% 0.00% 0.00% 99.94% +12668 +80487 +410555 62182 221616 16384 2.94% 0.00% 0.05% 97.00% +21587 +342769 +517566 23359 232696 16384 6.94% 0.00% 0.10% 92.96% +16581 +336068 +484574 18453 244330 16384 11.45% 0.00% 0.14% 88.41% +23608 +345023 +564130 19177 At 211063 requests per second and higher the performance looks the same. But at the lower rates there is a clear drop. The higher mean response time (difference between server TX and RX timestamps) indicates more of the provided TX timestamps are hardware timestamps and the chrony server timestamp statistics confirm that. So, my interpretation is that like with the earlier version of the patch it's trading performance for timestamp quality at lower rates, but unlike the earlier version it's not losing performance at the higher rates. That seems acceptable to me. Admins of busy servers might need to decide if they should keep HW timestamping enabled. In theory, chrony could have an option to do that automatically. Thanks, -- Miroslav Lichvar