From nobody Tue May 21 22:49:27 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1607454027; cv=none; d=zohomail.com; s=zohoarc; b=delKVGVXIjq2U+ErH+TV9NMPUQIykbhzsu0nr/pT1yK7KwXgk4WLaEfIo6nczS1qV8J0RogL3W1Py3DS73uWZyKdLHT+ZT1EbTM0GZO0E2x4hsY3uTMu4iLWppNiFhEb8wE68pkXpWgDYZRccfaM9TE7fvLeOllQsZ+cisZWLx8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1607454027; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=KouZ87yfLRxQM56hfbfm+nYHd9ItiwueK6AEwYEaOMc=; b=HsvqcSqPhGnMlYcynxSgiK5X+Q7KLTs5cVnzvmG/+adr50bfVYCkTd4l3q5e5EhYBWlelq5B8ma7sw5qWBh9Io7pHaQz74M6LxwFfaWpH4L0gcJ0BqKlCpe8GY+KCU7+Rsbc6KslwhuyZbaYBFhFcqxec6JfYBG1xK9xm1w6Yqc= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1607454027268455.36946717365254; Tue, 8 Dec 2020 11:00:27 -0800 (PST) Received: from localhost ([::1]:57720 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kmhzE-0001kw-Gl for importer@patchew.org; Tue, 08 Dec 2020 13:45:20 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59852) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kmhWw-0005Il-6s for qemu-devel@nongnu.org; Tue, 08 Dec 2020 13:16:06 -0500 Received: from mail-wm1-x32c.google.com ([2a00:1450:4864:20::32c]:50630) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kmhWq-0007vz-B7 for qemu-devel@nongnu.org; Tue, 08 Dec 2020 13:16:05 -0500 Received: by mail-wm1-x32c.google.com with SMTP id c198so2804592wmd.0 for ; Tue, 08 Dec 2020 10:15:59 -0800 (PST) Received: from orth.archaic.org.uk (orth.archaic.org.uk. [81.2.115.148]) by smtp.gmail.com with ESMTPSA id u12sm4978873wmu.28.2020.12.08.10.15.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Dec 2020 10:15:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=KouZ87yfLRxQM56hfbfm+nYHd9ItiwueK6AEwYEaOMc=; b=kc9Hqp/NhJhBbEDZKfwWn+V9FLMNI7zR/FD6Xnj2HUyF9l7MVQjaBa9lebNEtIX7ga whPB5Rt63EHvDxNTVvl31qalqWtE3sZaBSTw5hB8H7jlEuVasAT1jvatA8ykgUFBO0IV EWHsRutGNtE+HTJJ+2nY0HOoJs/meQyJJAWBbHNe4tOb/h/xVbZkIhLCS15oR2K8mhJo JlFSMqC6AWLMsPG9lmfOYdACSSyZ5B+580pVC9On20bX/Iz8b91jQmoY0My8PdgBZvJs 3anxM2ot/xDuAzm/GYeYjZ9HdG8LS52RfnET6XaZUCfu01pW6jkSWo57hLKUQbtqeJTi qGEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=KouZ87yfLRxQM56hfbfm+nYHd9ItiwueK6AEwYEaOMc=; b=McXrFKacJ7pl0GyKInB+FGyj3QoVy5ycGdIEWrX1LASldLAhO+bEF8xW84SIEINmMN zdKzKB5t4s/gSqM/+LeIb1u2C6+GHnf1R0bBFTsbytI4ziBMP5hjcWa58fNdkCqpqSXd tjpao382ilcO0X+baMCtO2yQoS/26kT8xIgl5uebEKM6dx0L0K3p/Tv0FkfbS4vIHu6i CR/K3pZG/mPwTYPZvoB+r4L5cHJZSNjVIJC52IyS8Q0b1fB03jsh0GgGQSx9QjHWRtj8 OXVid8KrGE10lFI0QLFJHC0wNEmSv5FQNPCH1vELejXn1WjqhcA+gKe4/BNwDcihgIRS z7fA== X-Gm-Message-State: AOAM530af9m618R9zqvUAnudlxTS6Jr1DAtXrO5GXt2fsXD25yJqsVZs pylIjv4JtIhcn4rEP9n7U0SNr/ldPzw84A== X-Google-Smtp-Source: ABdhPJwPpgLnK/wJqOkLEUj4RaghOH8VdRoVJ3szf0qt/85U1J2HM3DZDIrKSs7LgF8OZzuG23bZfg== X-Received: by 2002:a05:600c:40ca:: with SMTP id m10mr4990249wmh.54.1607451357780; Tue, 08 Dec 2020 10:15:57 -0800 (PST) From: Peter Maydell To: qemu-devel@nongnu.org Subject: [PATCH 1/4] clock: Introduce clock_ticks_to_ns() Date: Tue, 8 Dec 2020 18:15:51 +0000 Message-Id: <20201208181554.435-2-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201208181554.435-1-peter.maydell@linaro.org> References: <20201208181554.435-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::32c; envelope-from=peter.maydell@linaro.org; helo=mail-wm1-x32c.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Damien Hedde , Luc Michel , Aleksandar Rikalo , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" The clock_get_ns() API claims to return the period of a clock in nanoseconds. Unfortunately since it returns an integer and a clock's period is represented in units of 2^-32 nanoseconds, the result is often an approximation, and calculating a clock expiry deadline by multiplying clock_get_ns() by a number-of-ticks is unacceptably inaccurate. Introduce a new API clock_ticks_to_ns() which returns the number of nanoseconds it takes the clock to make a given number of ticks. This function can do the complete calculation internally and will thus give a more accurate result. Signed-off-by: Peter Maydell --- The 64x64->128 multiply is a bit painful for 32-bit and I guess in theory since we know we only want bits [95:32] of the result we could special-case it, but TBH I don't think 32-bit hosts merit much optimization effort these days. --- docs/devel/clocks.rst | 15 +++++++++++++++ include/hw/clock.h | 29 +++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst index e5da28e2111..aebeedbb95e 100644 --- a/docs/devel/clocks.rst +++ b/docs/devel/clocks.rst @@ -258,6 +258,21 @@ Here is an example: clock_get_ns(dev->my_clk_input)); } =20 +Calculating expiry deadlines +---------------------------- + +A commonly required operation for a clock is to calculate how long +it will take for the clock to tick N times; this can then be used +to set a timer expiry deadline. Use the function ``clock_ticks_to_ns()``, +which takes an unsigned 64-bit count of ticks and returns the length +of time in nanoseconds required for the clock to tick that many times. + +It is important not to try to calculate expiry deadlines using a +shortcut like multiplying a "period of clock in nanoseconds" value +by the tick count, because clocks can have periods which are not a +whole number of nanoseconds, and the accumulated error in the +multiplication can be significant. + Changing a clock period ----------------------- =20 diff --git a/include/hw/clock.h b/include/hw/clock.h index 81bcf3e505a..a9425d9fb14 100644 --- a/include/hw/clock.h +++ b/include/hw/clock.h @@ -16,6 +16,7 @@ =20 #include "qom/object.h" #include "qemu/queue.h" +#include "qemu/host-utils.h" =20 #define TYPE_CLOCK "clock" OBJECT_DECLARE_SIMPLE_TYPE(Clock, CLOCK) @@ -218,6 +219,34 @@ static inline unsigned clock_get_ns(Clock *clk) return CLOCK_PERIOD_TO_NS(clock_get(clk)); } =20 +/** + * clock_ticks_to_ns: + * @clk: the clock to query + * @ticks: number of ticks + * + * Returns the length of time in nanoseconds for this clock + * to tick @ticks times. Because a clock can have a period + * which is not a whole number of nanoseconds, it is important + * to use this function when calculating things like timer + * expiry deadlines, rather than attempting to obtain a "period + * in nanoseconds" value and then multiplying that by a number + * of ticks. + */ +static inline uint64_t clock_ticks_to_ns(const Clock *clk, uint64_t ticks) +{ + uint64_t ns_low, ns_high; + + /* + * clk->period is the period in units of 2^-32 ns, so + * (clk->period * ticks) is the required length of time in those + * units, and we can convert to nanoseconds by multiplying by + * 2^32, which is the same as shifting the 128-bit multiplication + * result right by 32. + */ + mulu64(&ns_low, &ns_high, clk->period, ticks); + return ns_low >> 32 | ns_high << 32; +} + /** * clock_is_enabled: * @clk: a clock --=20 2.20.1 From nobody Tue May 21 22:49:27 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1607453817; cv=none; d=zohomail.com; s=zohoarc; b=HghU38Jp08a5CHpywVeWJkMd3+O3XEUOcvrZTW+xJ2lkXFqNy5JyP5KK5mFLacYynJeC+QWhHtwDTGHgvl32P9Eg6JsS4dxH9OzMNXCdbMSz83/TJ/cTr9MnfMIu/zvC8xZ/gx3Iy4r5bGoce/acCfBYg8qoIJm714kjA/WM8mU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1607453817; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=SwadCJ02g06YVmm9WBr3OA6H8xYCnuJ8Eyeb77/KvE4=; b=ZP0vN/Aen3RAYzi4Jz8rhC1KUrGf1PosdkRJztsXIkIHzGbFe19hfdYiLd1itRchdKTAKxqMdUo5mJcONvibFpNO0kFJN+pnt1CmKdTkUfEOY5++EQCcWPUMq/eWXTajErjY0qD8q+LipWTSLosl5OEDUxhNbxgWD/mi3EPHzoQ= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1607453817300526.2769767133152; Tue, 8 Dec 2020 10:56:57 -0800 (PST) Received: from localhost ([::1]:57610 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kmiAS-0005JB-72 for importer@patchew.org; Tue, 08 Dec 2020 13:56:56 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59892) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kmhWy-0005JZ-3y for qemu-devel@nongnu.org; Tue, 08 Dec 2020 13:16:09 -0500 Received: from mail-wr1-x443.google.com ([2a00:1450:4864:20::443]:38691) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kmhWr-0007w4-7D for qemu-devel@nongnu.org; Tue, 08 Dec 2020 13:16:07 -0500 Received: by mail-wr1-x443.google.com with SMTP id r7so5963126wrc.5 for ; Tue, 08 Dec 2020 10:16:00 -0800 (PST) Received: from orth.archaic.org.uk (orth.archaic.org.uk. [81.2.115.148]) by smtp.gmail.com with ESMTPSA id u12sm4978873wmu.28.2020.12.08.10.15.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Dec 2020 10:15:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=SwadCJ02g06YVmm9WBr3OA6H8xYCnuJ8Eyeb77/KvE4=; b=BUc1NOklc4kh6Uy7ShIfNvT/fw/u2Py0Iw8IgOwo9zwtWmwbdakX+ntiGZSfl4k8Jm xXnefgnV9y4SdEygu6Z2pZ6BKzhvZzLer/7lCTe6TaGvSlCj6EHrbexMEG3cD4EaOtKY zGWZtf7ErHf6GuzmmCr8OwpGQbtaRReBb+7d++b0cdgfvV8267RG3Bv2J39X3MZrep2F MNQMymlZ2LlJXr2FHcsMDsga2IBdskWsjk9NkCN4xs7Z+nrpRdMJfywNU3iPOVS+4KfX bile6e7e8ZtcxpmIAu3vGQazR1v33+Iy+CSWDtnaAeCnuc5QXtTUx4x0jS7KR4v5ouo1 q2SA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=SwadCJ02g06YVmm9WBr3OA6H8xYCnuJ8Eyeb77/KvE4=; b=IyORiSCrci/RA5SaLTifWBhfgrDvvwaFOWdHKDjSYDlDVMZohcHTpj5GcUIBqpzKe1 Ofw34D6NP/HKxCztLir8pfK5+cP60JbKs9iEXvQ5hlkTSI8KdlIDppVowqmryUbHj3cl Zn7s50xOovT8FzNtfgux63GyFhKVlXxNvJJzq0V9fCKuLbO2Jl8KsqVRKp8sm+FVGo0O zOYx7aObrxGjOavTGXAb9xsIFeeYM3eqKHpTmjQ7UeT1PauDile2N2BhlHnOUIjvgu4k fqqDwHi4p7wSr0jN0nsEOfaftfTgXD+x6ot+HdTDeasPB1dXE1T3/tTCR/gWnkDoiM/l gOOQ== X-Gm-Message-State: AOAM531WuT6Fb7og1BKtzvieWmQ/Qj0rPJpBEGUKrViiKd6rVbPJVg1e SbnBmWMQG0yaBV3n+hD72dXrZFDmbdbleQ== X-Google-Smtp-Source: ABdhPJxZKMfGz8TRUAQVXYLhYh32JScuhaPq87clcsfkJ6mqime8WcBlaKLETc62zm0ssrIZ92dMKw== X-Received: by 2002:adf:fa0c:: with SMTP id m12mr26712057wrr.222.1607451359039; Tue, 08 Dec 2020 10:15:59 -0800 (PST) From: Peter Maydell To: qemu-devel@nongnu.org Subject: [PATCH 2/4] target/mips: Don't use clock_get_ns() in clock period calculation Date: Tue, 8 Dec 2020 18:15:52 +0000 Message-Id: <20201208181554.435-3-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201208181554.435-1-peter.maydell@linaro.org> References: <20201208181554.435-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::443; envelope-from=peter.maydell@linaro.org; helo=mail-wr1-x443.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Damien Hedde , Luc Michel , Aleksandar Rikalo , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Currently the MIPS code uses the old clock_get_ns() API to calculate a time length in nanoseconds: cpu->cp0_count_rate * clock_get_ns(MIPS_CPU(cpu)->clock) This relies on the clock having a period which is an exact number of nanoseconds. Switch to the new clock_ticks_to_ns() function, which does the multiplication internally at a higher precision. Signed-off-by: Peter Maydell Reviewed-by: Luc Michel Reviewed-by: Richard Henderson --- target/mips/cpu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/target/mips/cpu.c b/target/mips/cpu.c index 76d50b00b42..de15ec6068a 100644 --- a/target/mips/cpu.c +++ b/target/mips/cpu.c @@ -147,8 +147,8 @@ static void mips_cp0_period_set(MIPSCPU *cpu) { CPUMIPSState *env =3D &cpu->env; =20 - env->cp0_count_ns =3D cpu->cp0_count_rate - * clock_get_ns(MIPS_CPU(cpu)->clock); + env->cp0_count_ns =3D clock_ticks_to_ns(MIPS_CPU(cpu)->clock, + cpu->cp0_count_rate); assert(env->cp0_count_ns); } =20 --=20 2.20.1 From nobody Tue May 21 22:49:27 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1607453447; cv=none; d=zohomail.com; s=zohoarc; b=bQXlfU3vT5JRa+oSu7tqpYCcOg/O5CgO64TGjCZhze/fCUOXhkRnDr/Y9I9rmE6JKekEwex97ltaAq0BLFHY+dqKyQCBcfJ6CfXwIva4M8WjZlwjtPTyPM0dkoyJew07HS9sRx744QA2NZSZ9NF5zro7WP8ulaW5g97XMAexa1Y= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1607453447; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=UemC5541VEYHf/BEklXFjK6XVs4Wljvyr7YjA/NgPRE=; b=P/ChbF0d+iBNY9Um6usZzImEh4TIiu+WHPorU2G/mr0Mwkmx+cSvtjtJbd7e3AP68D8j2Z90hVNXUWY7ZQGq/tqVpE/iS559tHtwX2T17NmxecSWjqv9fGj3jESr61ZSs9WQyg07086Z0W/X1KxKa6igep5/R5YwLyMUofqlV2o= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1607453447694181.91091994902968; Tue, 8 Dec 2020 10:50:47 -0800 (PST) Received: from localhost ([::1]:39598 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kmi4U-00065M-EA for importer@patchew.org; Tue, 08 Dec 2020 13:50:46 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59916) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kmhX0-0005L3-OG for qemu-devel@nongnu.org; Tue, 08 Dec 2020 13:16:12 -0500 Received: from mail-wr1-x441.google.com ([2a00:1450:4864:20::441]:33197) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kmhWt-0007wB-Th for qemu-devel@nongnu.org; Tue, 08 Dec 2020 13:16:10 -0500 Received: by mail-wr1-x441.google.com with SMTP id r14so1531568wrn.0 for ; Tue, 08 Dec 2020 10:16:01 -0800 (PST) Received: from orth.archaic.org.uk (orth.archaic.org.uk. [81.2.115.148]) by smtp.gmail.com with ESMTPSA id u12sm4978873wmu.28.2020.12.08.10.15.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Dec 2020 10:15:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=UemC5541VEYHf/BEklXFjK6XVs4Wljvyr7YjA/NgPRE=; b=oDin9NQ5bjhtkP71wlYo3TFHoeVgTLvAwVdz70K03gZxR3k8aHx9mDe/+1QSzRlczp U/UA1phAYfVYHcIEr5LahsDE9gmCqLbG0Xu08NQkcvnAzNXFtkasNoFcpgTQ9L+v02Kv 3q9k56BDRKQygYVuUR5cGmHSU1k7rYoSkLTWj0zweEXc31+oUvJDT9NdxoV7Xk9EYTBP gPP48sSbwSh140aYlCwKy7ZoG2rJ7XGiY1IuoJ99asCmAgboqrkmvOvQ6yokf9nJMsEb 9wSnJG51sm/HyA91i3U+NpBwswqS7KbuAyLFtQ4FVt4grYHBK41j69F/qYWIBVXbqNAE WztQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=UemC5541VEYHf/BEklXFjK6XVs4Wljvyr7YjA/NgPRE=; b=aMhAzMxHZEiJDHoaVyr6qnCTMDE4XRa2zjrdfVfh0mjGG0gikJIsvZBzdkR3oRSyQ7 +8kvXenk2pz0iGiMQr+V/kb4WioaS3oSq6XMpEQcrh9XJVz3pcnfEJXtsj27nn0MJPGv enVsMSgnGkPHWYisBOaCvlvjIIyeNln02sFuSrelNZP0K1W4vkIVdD0t7HqsaotGoZBO hW6W3HkSNNqAsbkZpB0dZHhRjsInBD0BFuqm1T8+wALrNUFLCZi/vl7rNzr+T8BC5Nxp ojFaX607BrxdMpQwYQjxeHTNbSX6+BQkFIvUeQ1T4VCB6J8pCpWCpeuYbR++USVM3kOO Egow== X-Gm-Message-State: AOAM5339pWVcMsLhbRin5teA6V3qLVGH7jOxfrjUNRWekno/CUDBRt+I RGqWf4kU2vaPpQCUwdqQPRGCZwEgGBuiEg== X-Google-Smtp-Source: ABdhPJx0uGvjUh28BqCCwbaK/jSrZnfNTq+MJVUAX2bGweZQ+dXXOd49beXG+OKQdqIYs3XUFnM3qQ== X-Received: by 2002:a5d:4604:: with SMTP id t4mr25757550wrq.411.1607451360086; Tue, 08 Dec 2020 10:16:00 -0800 (PST) From: Peter Maydell To: qemu-devel@nongnu.org Subject: [PATCH 3/4] clock: Remove clock_get_ns() Date: Tue, 8 Dec 2020 18:15:53 +0000 Message-Id: <20201208181554.435-4-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201208181554.435-1-peter.maydell@linaro.org> References: <20201208181554.435-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::441; envelope-from=peter.maydell@linaro.org; helo=mail-wr1-x441.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, T_SPF_TEMPERROR=0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Damien Hedde , Luc Michel , Aleksandar Rikalo , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Remove the now-unused clock_get_ns() API and the CLOCK_PERIOD_TO_NS() macro that only it was using. Signed-off-by: Peter Maydell Reviewed-by: Luc Michel Reviewed-by: Richard Henderson --- docs/devel/clocks.rst | 17 +++++++++++++---- include/hw/clock.h | 6 ------ 2 files changed, 13 insertions(+), 10 deletions(-) diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst index aebeedbb95e..9a93d1361b4 100644 --- a/docs/devel/clocks.rst +++ b/docs/devel/clocks.rst @@ -238,8 +238,17 @@ object during device instance init. For example: Fetching clock frequency/period ------------------------------- =20 -To get the current state of a clock, use the functions ``clock_get()``, -``clock_get_ns()`` or ``clock_get_hz()``. +To get the current state of a clock, use the functions ``clock_get()`` +or ``clock_get_hz()``. + +``clock_get()`` returns the period of the clock in its fully precise +internal representation, as an unsigned 64-bit integer in units of +2^-32 nanoseconds. (For many purposes ``clock_ticks_to_ns()`` will +be more convenient; see the section below on expiry deadlines.) + +``clock_get_hz()`` returns the frequency of the clock, rounded to the +next lowest integer. This implies some inaccuracy due to the rounding, +so be cautious about using it in calculations. =20 It is also possible to register a callback on clock frequency changes. Here is an example: @@ -254,8 +263,8 @@ Here is an example: */ =20 /* do something with the new period */ - fprintf(stdout, "device new period is %" PRIu64 "ns\n", - clock_get_ns(dev->my_clk_input)); + fprintf(stdout, "device new period is %" PRIu64 "* 2^-32 ns\n", + clock_get(dev->my_clk_input)); } =20 Calculating expiry deadlines diff --git a/include/hw/clock.h b/include/hw/clock.h index a9425d9fb14..9c0b1eb4c3f 100644 --- a/include/hw/clock.h +++ b/include/hw/clock.h @@ -39,7 +39,6 @@ typedef void ClockCallback(void *opaque); * macro helpers to convert to hertz / nanosecond */ #define CLOCK_PERIOD_FROM_NS(ns) ((ns) * (CLOCK_PERIOD_1SEC / 1000000000ll= u)) -#define CLOCK_PERIOD_TO_NS(per) ((per) / (CLOCK_PERIOD_1SEC / 1000000000ll= u)) #define CLOCK_PERIOD_FROM_HZ(hz) (((hz) !=3D 0) ? CLOCK_PERIOD_1SEC / (hz)= : 0u) #define CLOCK_PERIOD_TO_HZ(per) (((per) !=3D 0) ? CLOCK_PERIOD_1SEC / (per= ) : 0u) =20 @@ -214,11 +213,6 @@ static inline unsigned clock_get_hz(Clock *clk) return CLOCK_PERIOD_TO_HZ(clock_get(clk)); } =20 -static inline unsigned clock_get_ns(Clock *clk) -{ - return CLOCK_PERIOD_TO_NS(clock_get(clk)); -} - /** * clock_ticks_to_ns: * @clk: the clock to query --=20 2.20.1 From nobody Tue May 21 22:49:27 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1607454227; cv=none; d=zohomail.com; s=zohoarc; b=Lsb0h9qs3dFcziekwOkNPL73/bJKWcuc7uep3FQK2k9kqtrm3z+3JlJPpyYT2IjcGZcWqtJZLlcuaYVShhdMVjwrUxxsmyBJO0WkZsV2xFw8h/Bt2CrQlbGAFuMyBnF9rlLsNHigwDk4yJpVZtE/lXrURarinOQCjCvWvwyeCOY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1607454227; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=rsusvVmbp8UtSIK1LPtaov69Vpog2i9qOUwwDMskU2I=; b=EPTkV3uP74KrSD5E4GdZWVHr9dBcwPvnrcvk1OLYRssJ0CqsJXtjDNWFwnPFN8K63fvKx51ZmmbkzGiffR9UKnFJ+g2+GzQMWWV4YcAnjCTAT2sJsekCTtobtIAFq8TTRZ2Ofzzo9Zmt/tq4X/vhfBmQsQUTX8CJkn3c8PF0xMI= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1607454227265393.91626089427393; Tue, 8 Dec 2020 11:03:47 -0800 (PST) Received: from localhost ([::1]:59228 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kmi0K-0002MF-53 for importer@patchew.org; Tue, 08 Dec 2020 13:46:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59870) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kmhWw-0005Iy-N2 for qemu-devel@nongnu.org; Tue, 08 Dec 2020 13:16:07 -0500 Received: from mail-wr1-x429.google.com ([2a00:1450:4864:20::429]:33737) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kmhWu-0007wI-HM for qemu-devel@nongnu.org; Tue, 08 Dec 2020 13:16:06 -0500 Received: by mail-wr1-x429.google.com with SMTP id r14so1531613wrn.0 for ; Tue, 08 Dec 2020 10:16:02 -0800 (PST) Received: from orth.archaic.org.uk (orth.archaic.org.uk. [81.2.115.148]) by smtp.gmail.com with ESMTPSA id u12sm4978873wmu.28.2020.12.08.10.16.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Dec 2020 10:16:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=rsusvVmbp8UtSIK1LPtaov69Vpog2i9qOUwwDMskU2I=; b=h2ATfoOfy+TtIs6mm776iESpSRHVWTZ9OCtpa/Rb2BGWsVFL7fU4/2KNuemzORIpkX 8WtDp7+z7EGEmVX2mrwEL9smse3P8N6VhoPb1IVmp5yB5W12ScYrDTlTydmB5WprOuh/ 8vZIybbxHBOK12AXmcMZCZKkPDWCl7Al6Q6aPLdNqOjp97O5gFttEuwGdmv9SoPzllEe pcHo3gspjfb9Hx+T0kv75OOmIuztlEvD7cOIosJGs01XfXxWR56h1ME6kCZ3UIcrmO9R D9mdJNthUDhuNEtoChLPN02j8Atd7aWzcGEYnHozi9ER6cW5Hb/bL8v4QODiWBRv645z omCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=rsusvVmbp8UtSIK1LPtaov69Vpog2i9qOUwwDMskU2I=; b=DGNHEwtwnUlCT4o98dLD4ijv21F8cZ3/NrFXWVeJo89et5xIedg7bi9an+sMPY4ct3 MzbbphCaqCHohi9A90TMTfl0i2SR/WaOwhimwHMCMefn8B4S8JhrKex/tT8Gapo/4Lve XsclFf1jp8ciNHi6ZmUXDtFECeMu2sJswlokuvp7ctXXsguFOnvfmgWqaWCKOutFep1d jKEfu6xZTKjv7iS7FQoYdwNXJirh+FvljSkZs6n5YVITDft2XJqr/AxexDVFhvJ5nCEt AHiQRdr2+w67g/57ghICKteATDc9xbKVUhC6jOPnY+L8+LbRlHvc4U9VgcwXhTkUqy6G z5CA== X-Gm-Message-State: AOAM530xZvpQNn6gK4ZkWvaXkNfBModz3eRFElE/cw72ua5zF+OkPzwv UnvadfftqQFkV2WWqKdyLbqpeuUDNR4SFQ== X-Google-Smtp-Source: ABdhPJx4cBKQMUYUxJRttpZJJdyw+ZuXFGXNfImKdemxxc6qeVdfNqKbNtL9aFSmcMmDQVxDNK/ltw== X-Received: by 2002:adf:9525:: with SMTP id 34mr3378591wrs.389.1607451361253; Tue, 08 Dec 2020 10:16:01 -0800 (PST) From: Peter Maydell To: qemu-devel@nongnu.org Subject: [PATCH 4/4] clock: Define and use new clock_display_freq() Date: Tue, 8 Dec 2020 18:15:54 +0000 Message-Id: <20201208181554.435-5-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201208181554.435-1-peter.maydell@linaro.org> References: <20201208181554.435-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::429; envelope-from=peter.maydell@linaro.org; helo=mail-wr1-x429.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Damien Hedde , Luc Michel , Aleksandar Rikalo , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" It's common to want to print a human-readable indication of a clock's frequency. Provide a utility function in the clock API to return a string which is a displayable representation of the frequency, and use it in qdev-monitor.c. Before: (qemu) info qtree [...] dev: xilinx,zynq_slcr, id "" clock-in "ps_clk" freq_hz=3D3.333333e+07 mmio 00000000f8000000/0000000000001000 After: dev: xilinx,zynq_slcr, id "" clock-in "ps_clk" freq_hz=3D33.3 MHz mmio 00000000f8000000/0000000000001000 Signed-off-by: Peter Maydell Reviewed-by: Luc Michel Reviewed-by: Richard Henderson --- This is based on Philippe's patch "qdev-monitor: Display frequencies scaled to SI unit" but I have abstracted out the "prettified string" into the clock API. --- docs/devel/clocks.rst | 5 +++++ include/hw/clock.h | 12 ++++++++++++ hw/core/clock.c | 6 ++++++ softmmu/qdev-monitor.c | 6 +++--- 4 files changed, 26 insertions(+), 3 deletions(-) diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst index 9a93d1361b4..cf8067542a1 100644 --- a/docs/devel/clocks.rst +++ b/docs/devel/clocks.rst @@ -267,6 +267,11 @@ Here is an example: clock_get(dev->my_clk_input)); } =20 +If you are only interested in the frequency for displaying it to +humans (for instance in debugging), use ``clock_display_freq()``, +which returns a prettified string-representation, e.g. "33.3 MHz". +The caller must free the string with g_free() after use. + Calculating expiry deadlines ---------------------------- =20 diff --git a/include/hw/clock.h b/include/hw/clock.h index 9c0b1eb4c3f..7bc9afb0800 100644 --- a/include/hw/clock.h +++ b/include/hw/clock.h @@ -252,4 +252,16 @@ static inline bool clock_is_enabled(const Clock *clk) return clock_get(clk) !=3D 0; } =20 +/** + * clock_display_freq: return human-readable representation of clock frequ= ency + * @clk: clock + * + * Return a string which has a human-readable representation of the + * clock's frequency, e.g. "33.3 MHz". This is intended for debug + * and display purposes. + * + * The caller is responsible for freeing the string with g_free(). + */ +char *clock_display_freq(Clock *clk); + #endif /* QEMU_HW_CLOCK_H */ diff --git a/hw/core/clock.c b/hw/core/clock.c index 8c6af223e7c..76b5f468b6e 100644 --- a/hw/core/clock.c +++ b/hw/core/clock.c @@ -12,6 +12,7 @@ */ =20 #include "qemu/osdep.h" +#include "qemu/cutils.h" #include "hw/clock.h" #include "trace.h" =20 @@ -111,6 +112,11 @@ static void clock_disconnect(Clock *clk) QLIST_REMOVE(clk, sibling); } =20 +char *clock_display_freq(Clock *clk) +{ + return freq_to_str(clock_get_hz(clk)); +} + static void clock_initfn(Object *obj) { Clock *clk =3D CLOCK(obj); diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c index bf79d0bbcd9..6263d600026 100644 --- a/softmmu/qdev-monitor.c +++ b/softmmu/qdev-monitor.c @@ -747,11 +747,11 @@ static void qdev_print(Monitor *mon, DeviceState *dev= , int indent) } } QLIST_FOREACH(ncl, &dev->clocks, node) { - qdev_printf("clock-%s%s \"%s\" freq_hz=3D%e\n", + g_autofree char *freq_str =3D clock_display_freq(ncl->clock); + qdev_printf("clock-%s%s \"%s\" freq_hz=3D%s\n", ncl->output ? "out" : "in", ncl->alias ? " (alias)" : "", - ncl->name, - CLOCK_PERIOD_TO_HZ(1.0 * clock_get(ncl->clock))); + ncl->name, freq_str); } class =3D object_get_class(OBJECT(dev)); do { --=20 2.20.1