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 969DCA0351; Mon, 18 Nov 2019 17:43:40 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 13E7DB62; Mon, 18 Nov 2019 17:43:40 +0100 (CET) Received: from mail-lf1-f50.google.com (mail-lf1-f50.google.com [209.85.167.50]) by dpdk.org (Postfix) with ESMTP id 35987A69; Mon, 18 Nov 2019 17:43:39 +0100 (CET) Received: by mail-lf1-f50.google.com with SMTP id f18so2035972lfj.6; Mon, 18 Nov 2019 08:43:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mDY2xuuDVJPo6jIODQ5v80GcuKZjTy6ziAxzpuwzinc=; b=eAvHRE4qeRQcRWwmd3noTNOoPUuS5YFNu506OGHjVSmb4jNhkb+QTn8JAmr6XBazAn 0rBDYPT6GOzhxyfmH2TkvwR0TAq4V1GGupDJQBCwbzpCy2kCAdehNM2N73ioq8JcOboi R3sxK55vkP3tcWxJRr/lPUrpafZ5bgBl2eUPgpkUGIg/OTJwLQ3Zvd+o0XLSBEZm2TpN JytQvMXS6UC+FkfzoWi7/BMuQNhZOu8bs0PKyjr441PbwSnsR+56bn98m9E6443fm0Nk HjabK2UAUNJHUnmvWPz2BeEn2XD0IS+inH+MNn48xtibP9AC5FmlD48oIHbO2ts3upbr QZfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mDY2xuuDVJPo6jIODQ5v80GcuKZjTy6ziAxzpuwzinc=; b=XZYFE+lqajTiULDa+7z/sNRoVsO8YFjaYIKHcaLGiHud7ZnqY5msh4edAw4mRIyQWs alcExhcK+54kY02ODKIkLQQO7/HQtQBiswhqbIOi9MmqW27WGRywVIf8XG0ddJUxgMK2 6PJDWjNstrlTfAsW0+MFjA15NXyA1R6pPiqqfjGeK4sZsIvcbvYV3wekkXkGvJErQR/M A5ep0Y2UCn3ZRflGCOti7FV43RwGIyjTSvsY1OsG1Xy0XlLcUlMjlh9EhopirEeGOMp0 6lGMyKh2RJl0/Wsx2olYUW6cOzQj+ekVom23xzN+v3nh8HQIsvp9ByR1GdDWTF4mNr59 /bSw== X-Gm-Message-State: APjAAAW89Wm1HEsMfnpZpvgsxDlVnfL4KQ53m7xK7hPtWeT/s4SswCmW 6xYIsqV/waqVrjxUwM2WTIf4C/lp1FDEmZpiAPw= X-Google-Smtp-Source: APXvYqxPezPteO0qB3ici/GBbO6dpCRvMnBxTDjHeNue2HTkLoDMIjbrjF6xc+bmtYOogu+t2r10TCSgkKmcc4uX69M= X-Received: by 2002:a05:6512:15b:: with SMTP id m27mr234967lfo.53.1574095418494; Mon, 18 Nov 2019 08:43:38 -0800 (PST) MIME-Version: 1.0 References: <20191113091927.GA1501@bricha3-MOBL.ger.corp.intel.com> <70f4e9f0-70f7-aa4a-6c5d-c24308d196c2@intel.com> <3c014e01-3635-df19-a11c-2db09b03d423@intel.com> In-Reply-To: From: Venumadhav Josyula Date: Mon, 18 Nov 2019 22:13:24 +0530 Message-ID: To: "Burakov, Anatoly" Cc: Bruce Richardson , users@dpdk.org, dev@dpdk.org, Venumadhav Josyula Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: Re: [dpdk-dev] time taken for allocation of mempool. 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" Hi Anatoly, After using iova-mode=va, i see my ports are not getting detected ? I thought it's working but I see following problem what could be the problem? i) I see allocation is faster ii) But my ports are not getting detected I take my word back that it entirely working.. Thanks, Regards, Venu On Thu, 14 Nov 2019 at 15:27, Burakov, Anatoly wrote: > On 14-Nov-19 9:50 AM, Venumadhav Josyula wrote: > > Hi Anatoly, > > > > Thanks for quick response. We want to understand, if there will be > > performance implications because of iova-mode being va. We want to > > understand, specifically in terms following > > > > * cache misses > > * Branch misses etc > > * translation of va addr -> phy addr when packet is receieved > > > > There will be no impact whatsoever. You mentioned that you were already > using VFIO, so you were already making use of IOMMU*. Cache/branch > misses are independent of IOVA layout, and translations are done by the > hardware (in either IOVA as PA or IOVA as VA case - IOMMU doesn't care > what you program it with, it still does the translation, even if it's a > 1:1 IOVA-to-PA mapping), so there is nothing that can cause degradation. > > In fact, under some circumstances, using IOVA as VA mode can be used to > get performance /gains/, because the code can take advantage of the fact > that there are large IOVA-contiguous segments and no page-by-page > allocations. Some drivers (IIRC octeontx mempool?) even refuse to work > in IOVA as PA mode due to huge overheads of page-by-page buffer offset > tracking. > > TL;DR you'll be fine :) > > * Using an IOMMU can /theoretically/ affect performance due to hardware > IOVA->PA translation and IOTLB cache misses. In practice, i have never > been able to observe /any/ effect whatsoever on performance when using > IOMMU vs. without using IOMMU, so this appears to not be a concern /in > practice/. > > > Thanks and regards > > Venu > > > > On Thu, 14 Nov 2019 at 15:14, Burakov, Anatoly > > > wrote: > > > > On 13-Nov-19 9:01 PM, Venumadhav Josyula wrote: > > > Hi Anatoly, > > > > > > By default w/o specifying --iova-mode option is iova-mode=pa by > > default ? > > > > > > Thanks > > > Venu > > > > > > > In 18.11, there is a very specific set of circumstances that will > > default to IOVA as VA mode. Future releases have become more > > aggressive, > > to the point of IOVA as VA mode being the default unless asked > > otherwise. So yes, it is highly likely that in your case, IOVA as PA > is > > picked as the default. > > > > -- > > Thanks, > > Anatoly > > > > > -- > Thanks, > Anatoly >