From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id BD7F2A0613 for ; Tue, 27 Aug 2019 10:14:08 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 9793A1C02E; Tue, 27 Aug 2019 10:14:07 +0200 (CEST) Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id BF64F1C02A for ; Tue, 27 Aug 2019 10:14:06 +0200 (CEST) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Aug 2019 01:14:05 -0700 X-IronPort-AV: E=Sophos;i="5.64,436,1559545200"; d="scan'208";a="185218407" Received: from bricha3-mobl.ger.corp.intel.com ([10.237.221.46]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Aug 2019 01:14:04 -0700 Date: Tue, 27 Aug 2019 09:14:01 +0100 From: Bruce Richardson To: Jim Harris Cc: dev@dpdk.org, anatoly.burakov@intel.com Message-ID: <20190827081400.GA1740@bricha3-MOBL.ger.corp.intel.com> References: <156646334762.14099.13593080473257757748.stgit@jrharri1-skx> <156682708634.28714.543470193614987025.stgit@jrharri1-skx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <156682708634.28714.543470193614987025.stgit@jrharri1-skx> User-Agent: Mutt/1.11.4 (2019-03-13) Subject: Re: [dpdk-dev] [PATCH v5] eal: use memzone to share tsc hz with secondary processes X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Mon, Aug 26, 2019 at 06:44:46AM -0700, Jim Harris wrote: > Ideally, get_tsc_freq_arch() is able to provide the > TSC rate using arch-specific means. When that is not > possible, DPDK reverts to calculating the TSC rate with > a 100ms nanosleep or 1s sleep. The latter occurs more > frequently in VMs which often do not have access to the > data they need from arch-specific means (CPUID leaf 0x15 > or MSR 0xCE on x86). > > In secondary processes, the extra 100ms is especially > noticeable and consumes the bulk of rte_eal_init() > execution time. To resolve this extra delay, have > the primary process put the TSC rate into a shared > memory region that the secondary process can lookup. > > Reduces rte_eal_init() execution time in a secondary > process from 165ms to 66ms on my test system. > > Signed-off-by: Jim Harris > --- I think using shared memory is a lot simpler to manage, so LGTM. Acked-by: Bruce Richardson