From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.sgi.com [192.48.180.66]) by ml01.01.org (Postfix) with ESMTP id ED33C1A1DF5 for ; Thu, 11 Aug 2016 06:41:15 -0700 (PDT) Received: from xmail.sgi.com (pv-excas3-dc21.corp.sgi.com [137.38.106.11]) by relay1.corp.sgi.com (Postfix) with ESMTP id EF4FD8F8035; Thu, 11 Aug 2016 06:41:14 -0700 (PDT) Received: from [128.162.232.243] (128.162.232.243) by xmail.sgi.com (137.38.106.6) with Microsoft SMTP Server (TLS) id 14.3.224.2; Thu, 11 Aug 2016 08:41:14 -0500 To: Star Zeng , References: <1470883079-4472-1-git-send-email-star.zeng@intel.com> CC: Michael D Kinney , Liming Gao From: "Brian J. Johnson" Message-ID: Date: Thu, 11 Aug 2016 08:41:13 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1470883079-4472-1-git-send-email-star.zeng@intel.com> X-Originating-IP: [128.162.232.243] Subject: Re: [PATCH] PcAtChipsetPkg AcpiTimerLib: Get more accurate TSC Frequency X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Aug 2016 13:41:16 -0000 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 8bit On 08/10/2016 09:37 PM, Star Zeng wrote: > Minimize the code overhead between the two TSC reads by adding > new internal API to calculate TSC Frequency instead of reusing > MicroSecondDelay (). Why not just use the MSR_PLATFORM_INFO (0xce) register bits 15..8, on CPUs where it's available, to read the TSC frequency directly? -- Brian J. Johnson -------------------------------------------------------------------- My statements are my own, are not authorized by SGI, and do not necessarily represent SGI’s positions.