From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <dev-bounces@dpdk.org> Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id DD6EDA0613 for <public@inbox.dpdk.org>; Tue, 27 Aug 2019 14:04:23 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 0EA9F1C0B0; Tue, 27 Aug 2019 14:04:23 +0200 (CEST) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id E3C361C0AC for <dev@dpdk.org>; Tue, 27 Aug 2019 14:04:21 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Aug 2019 05:04:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,437,1559545200"; d="scan'208";a="209723925" Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.237.220.108]) ([10.237.220.108]) by fmsmga002.fm.intel.com with ESMTP; 27 Aug 2019 05:04:19 -0700 To: Jim Harris <james.r.harris@intel.com>, dev@dpdk.org, bruce.richardson@intel.com References: <156646334762.14099.13593080473257757748.stgit@jrharri1-skx> <156682708634.28714.543470193614987025.stgit@jrharri1-skx> From: "Burakov, Anatoly" <anatoly.burakov@intel.com> Message-ID: <a88a02d3-5c67-ed1e-306c-339067dfdc4c@intel.com> Date: Tue, 27 Aug 2019 13:04:18 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <156682708634.28714.543470193614987025.stgit@jrharri1-skx> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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 <dev.dpdk.org> List-Unsubscribe: <https://mails.dpdk.org/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://mails.dpdk.org/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://mails.dpdk.org/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> Errors-To: dev-bounces@dpdk.org Sender: "dev" <dev-bounces@dpdk.org> On 26-Aug-19 2:44 PM, 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 <james.r.harris@intel.com> > --- I think this is a bad idea. If you're allocating something, you're supposed to free it in rte_eal_cleanup(). If you don't, that memory leaks (i.e. there are leftover hugepages after process exit). Since both primary and secondary are referencing it (even if only at init), there is no safe way to free this memzone. -- Thanks, Anatoly