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[2620:137:e000::3:1]) by mx.google.com with ESMTPS id bd7-20020a170902830700b001c9b129a665si333242plb.238.2023.11.22.20.11.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Nov 2023 20:11:11 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) client-ip=2620:137:e000::3:1; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b="ob/WMaSz"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by morse.vger.email (Postfix) with ESMTP id 55A19807CB4E; Wed, 22 Nov 2023 20:11:09 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at morse.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232912AbjKWEKy (ORCPT + 99 others); Wed, 22 Nov 2023 23:10:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232688AbjKWEKx (ORCPT ); Wed, 22 Nov 2023 23:10:53 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E545100 for ; Wed, 22 Nov 2023 20:11:00 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 50803C433C7; Thu, 23 Nov 2023 04:10:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1700712659; bh=vEGs5HAbjF1IAM1gT6KyCx139kNtp9F8hRI7yxkVjjM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ob/WMaSz5Puzesg6kIs0WCLO0Ey5+KAdsoLiBDcp/oMg2ahAG2r/ibJLtOD+W6iJn n279jAkbaKCxO5BeXXxQQoabBZg652kQ0j4V73Oouz36u2S9z95o5EpwRHKuh22gOQ F5ItVw5kQEhfxeDVdsI1aDUsSp4x1kurKleSiJt1vKL0gcK1tjyBm/KzEwX4/SlxQQ NU0aKWXCX0iZj04V+SLPfREzoJj5FEs7Nb4fQo8mJK9+NUq7hevNJBNpwvdJhZ2bfF hPPBHqNAA84FNqbubT3znkYm6kD5VpoYgU0vToxP11vB05s80+kJ71L5WvpGJNdkXu /HvGmk+0tNhUw== Date: Wed, 22 Nov 2023 20:10:58 -0800 From: Jakub Kicinski To: Sagi Maimon Cc: richardcochran@gmail.com, reibax@gmail.com, davem@davemloft.net, rrameshbabu@nvidia.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, maheshb@google.com Subject: Re: [PATCH v1] ptp: add PTP_MULTI_CLOCK_GET ioctl Message-ID: <20231122201058.0bfb07a9@kernel.org> In-Reply-To: <20231122074352.473943-1-maimon.sagi@gmail.com> References: <20231122074352.473943-1-maimon.sagi@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-1.2 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on morse.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (morse.vger.email [0.0.0.0]); Wed, 22 Nov 2023 20:11:09 -0800 (PST) On Wed, 22 Nov 2023 09:43:52 +0200 Sagi Maimon wrote: > Some user space applications need to read some clocks. > Each read requires moving from user space to kernel space. > This asymmetry causes the measured offset to have a significant error. Please CC maheshb@google.com on v2, he was doing something similar recently.