From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=2a00:1450:400c:c0c::242; helo=mail-wr0-x242.google.com; envelope-from=julien.grall@linaro.org; receiver=edk2-devel@lists.01.org Received: from mail-wr0-x242.google.com (mail-wr0-x242.google.com [IPv6:2a00:1450:400c:c0c::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 53AE4203525ED for ; Thu, 26 Oct 2017 04:02:14 -0700 (PDT) Received: by mail-wr0-x242.google.com with SMTP id g90so2757159wrd.6 for ; Thu, 26 Oct 2017 04:06:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=to:cc:from:subject:message-id:date:user-agent:mime-version :content-language:content-transfer-encoding; bh=IKLRRfyIdhsOHVe9GJi+UMeB2L+Vtt8j95I7KVVKe2M=; b=GMnNtZsnyqWiaiMxdvamQ8V4nNYpVpZ2dKoH+ZNFobrkko4F65ifQXBx7/ftbjQdNN D9P+6JVKZGxF7jxcCgEd0tocAjqFZkvnWUQpQtCdA72nUnEZ/og7h3eMK/QufkgYC9I7 V8GQDn8X24rgzYOztiEjVQki114YRk37LinOo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:from:subject:message-id:date:user-agent :mime-version:content-language:content-transfer-encoding; bh=IKLRRfyIdhsOHVe9GJi+UMeB2L+Vtt8j95I7KVVKe2M=; b=IphiIMUd+PO+T934GTgYcnvr9GYXaC6CEpPa3+rgnaKQVXA7PZyGTUdcC/XXKiKuNc zV/Kiyffj/Xin/2MU2UCnwcT0fGMQU3jHNzQcRJaTeX+rMJvhn2QSd37MD2LLUdvdmbJ kH4QtkIPDpSCTH6/pQOdBXve+tvhPA287mPaBnh1WQYPsVrf5gaqdMcR4EWmAwh+BAl5 czIYOKkeSDSdDlG2bqzRmnbYiXDBBJ61H+zEFkgzbpbUcgOu6ygu49AG/uoC/kbE+E5w TJmtrWAvo5TmDV1icI+hzntJZzbOElw/hE0jKMdcLaFlx20IuNawNCEUGpHFKCGTNzJX 51Wg== X-Gm-Message-State: AMCzsaWnFn1X/wzhNptpFu+JpQXQBsuwTJ8C3TmFu65Sp9aI5XYkts8l irvQvN1C91Ut0oxLLuR3Cgj0JQ== X-Google-Smtp-Source: ABhQp+TRMv1ucE7WRswpBZuX3flEBBbcWaKKZBZ5HAomBheuSyyrURQNpAbzORyDxulowKY/xRdmpQ== X-Received: by 10.223.161.210 with SMTP id v18mr5200741wrv.76.1509015958675; Thu, 26 Oct 2017 04:05:58 -0700 (PDT) Received: from ?IPv6:::1? ([2001:41d0:1:6c23::1]) by smtp.gmail.com with ESMTPSA id 61sm3828646wrg.58.2017.10.26.04.05.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 26 Oct 2017 04:05:58 -0700 (PDT) To: edk2-devel-01 , star.zeng@intel.com, heyi.guo@linaro.org, ruiyu.ni@intel.com, Laszlo Ersek Cc: Anthony PERARD , Leif Lindholm , Ard Biesheuvel From: Julien Grall Message-ID: <7516a301-dfbb-5bd4-5e1e-ccd18c26db30@linaro.org> Date: Thu, 26 Oct 2017 12:05:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 Subject: Xen Console input very slow in recent UEFI X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Oct 2017 11:02:14 -0000 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Hi all, I was doing more testing of UEFI in Xen guests and noticed some slow down when using the shell. The characters are only echoed after a second or two that is a bit annoying. The change that introduced this issue is 4cf3f37c87 "MdeModulePkg SerialDxe: Process timeout consistently in SerialRead". The Serial Driver for Xen PV console is very simple (see OvmfPkg/Library/XenConsoleSerialPortLib). So I am not sure where the root cause is. Would anyone have any tips on it? Cheers, -- Julien Grall