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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19EAFC433EF for ; Mon, 28 Feb 2022 13:57:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235250AbiB1N6Z (ORCPT ); Mon, 28 Feb 2022 08:58:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52154 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236937AbiB1N6T (ORCPT ); Mon, 28 Feb 2022 08:58:19 -0500 Received: from mail-oo1-xc30.google.com (mail-oo1-xc30.google.com [IPv6:2607:f8b0:4864:20::c30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A6A92AC58; Mon, 28 Feb 2022 05:57:30 -0800 (PST) Received: by mail-oo1-xc30.google.com with SMTP id i6-20020a4ac506000000b0031c5ac6c078so18823825ooq.6; Mon, 28 Feb 2022 05:57:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=OQXq8SH7J2jGjbN+Ln0Krx+hZyTKyM2L283Eje0Rl+s=; b=o+Icet+A3e3amogcnwE0LZFgYCS1c3zcxIEg9oYMUgh7aJx9LZ5aWKNkJfS4Pq2x/O MWldII8xSmeLGFITWzgOlLaNe8pAwkXHMPhjG08dSq4Qof0rtBefeQY3NqtkewnvZMA0 ly1la7NZVfTV2bIEh+o7w0J3UHB+cEe+7QcaLSRtioFrERv4DNrTuvLL2fAB7q/j/UMZ uTTMgZHed4j/jTiMkAOSwrNuvtN5lYtQCTOU0Kf48CjeEPLWR/sr+oSmD5DAwUbIpeAT 4ruElN01gl/Y+L85OTriEsX7fXZKPo0h+k+FfkXBEdVSfZCAqOtlRlBsyX3qV2eee/p7 G1rA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:message-id:date:mime-version:user-agent :subject:content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=OQXq8SH7J2jGjbN+Ln0Krx+hZyTKyM2L283Eje0Rl+s=; b=FHyUQZPDzddeXIxn2zWOrckhYWIGX4idEMRGcXXluIHRnm6BNYZ2w9dSEZPdveQpz+ Dh5HFquRUozEZICgOcN+cX/tMF4cjb0XVfcqfDeVoguTYayt+WrUGdLfEET65NqvnC38 p0KTw+WKRcxoagukkBDhd4Sr26U8Xw8yE24Jsoe9Ff4ZBO8c33ar0mPt/I/V9ESr0X65 ptjJF7xy6KDlerJMEJTTYpnqxqhz11cJs4msaf7TSGVGbMqtMOmev8nD2LwJKuc8da9v jNLR/WzzMPYFE2TjN+S+vlcNCaEQQV56NWS/o5HOGJyLRbMVpKblXn827jjOMJTgGDP/ TAhw== X-Gm-Message-State: AOAM533AR7GjRvFWThOVT3dpmD7yWE7mM33uqsL5PJMdscGcGbUqXPEs wJRJBD5188bpLROJhfFw3pgwlvsRY0A= X-Google-Smtp-Source: ABdhPJzpjJxKssZapkzltQ3XzA7dQSO9RfA/0OKeQZG1pM0V87IaqJKFXghJvuuE6QdlpO/bQjqaLA== X-Received: by 2002:a05:6870:7c07:b0:d7:e5c:62ac with SMTP id je7-20020a0568707c0700b000d70e5c62acmr4494840oab.54.1646056649864; Mon, 28 Feb 2022 05:57:29 -0800 (PST) Received: from ?IPV6:2600:1700:e321:62f0:329c:23ff:fee3:9d7c? ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id z26-20020a0568301dba00b005ad0fc5abe4sm5050787oti.16.2022.02.28.05.57.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 28 Feb 2022 05:57:29 -0800 (PST) Sender: Guenter Roeck Message-ID: Date: Mon, 28 Feb 2022 05:57:27 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v2 0/2] ic2: mux: pca9541: add delayed-release support Content-Language: en-US To: Zev Weiss , linux-i2c@vger.kernel.org, Peter Rosin , Rob Herring Cc: openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org References: <20220201001810.19516-1-zev@bewilderbeest.net> From: Guenter Roeck In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/28/22 00:43, Zev Weiss wrote: > On Mon, Jan 31, 2022 at 04:18:08PM PST, Zev Weiss wrote: >> Hello, >> >> This series adds support for a new pca9541 device-tree property >> ("release-delay-us"), which delays releasing ownership of the bus >> after a transaction for a configurable duration, anticipating that >> another transaction may follow shortly.  By avoiding a >> release/reacquisition between transactions, this can provide a >> substantial performance improvement for back-to-back operations -- on >> a Delta AHE-50DC (ASPEED AST1250) system running OpenBMC with dozens >> of LM25066 PMICs on PCA9541-arbitrated busses, a setting of 10000 (10 >> ms) reduces the median latency the psusensor daemon's hwmon sysfs file >> reads from 2.28 ms to 0.99 ms (a 57% improvement). >> > > Ping...Guenter, any thoughts on this? > It sounds reasonable to me, but I don't have access to hardware anymore to test it, so I have no means to confirm that it actually works. Guenter