From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout2.w1.samsung.com (mailout2.w1.samsung.com [210.118.77.12]) by dpdk.org (Postfix) with ESMTP id 538CB1B5D0 for ; Mon, 26 Nov 2018 15:32:05 +0100 (CET) Received: from eucas1p2.samsung.com (unknown [182.198.249.207]) by mailout2.w1.samsung.com (KnoxPortal) with ESMTP id 20181126143204euoutp0245b60c43f5befb10cc1c4a9247d20fa1~qsxTNCJYD0279502795euoutp02e for ; Mon, 26 Nov 2018 14:32:04 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.w1.samsung.com 20181126143204euoutp0245b60c43f5befb10cc1c4a9247d20fa1~qsxTNCJYD0279502795euoutp02e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1543242724; bh=UngT2ygFENxfOC0Zw75KOdmXME4c5dYAKyLSrGauKBk=; h=Subject:To:From:Date:In-Reply-To:References:From; b=UT3JIS7Drd2I7LoXJK8MijDm7diuY+7p1ZLimEVAkxe+hDtPR7mEfVPIeMvHSQI3y +6ZE3vZG2UmbKQAzTuMFQsVxXdHVlqUWwxIEubkzEbaeIV5+yv9Syi1uZ7Th4o8x6E 2/4tswKJjOv43L6TUmhtm+kmmXkJwwEa7gzEYTcY= Received: from eusmges2new.samsung.com (unknown [203.254.199.244]) by eucas1p2.samsung.com (KnoxPortal) with ESMTP id 20181126143203eucas1p2de0ce5f7ed6a8891acbc7f5f54a6742b~qsxSvDkHR1632216322eucas1p2e; Mon, 26 Nov 2018 14:32:03 +0000 (GMT) Received: from eucas1p1.samsung.com ( [182.198.249.206]) by eusmges2new.samsung.com (EUCPMTA) with SMTP id F9.64.04294.3E30CFB5; Mon, 26 Nov 2018 14:32:03 +0000 (GMT) Received: from eusmtrp1.samsung.com (unknown [182.198.249.138]) by eucas1p2.samsung.com (KnoxPortal) with ESMTPA id 20181126143202eucas1p2c8387dc0bbb3f6e0623b3b545e23d299~qsxR_QjJ81632216322eucas1p2b; Mon, 26 Nov 2018 14:32:02 +0000 (GMT) Received: from eusmgms2.samsung.com (unknown [182.198.249.180]) by eusmtrp1.samsung.com (KnoxPortal) with ESMTP id 20181126143202eusmtrp13e0d68812e695b0d3f0bcde6ee4c88a3~qsxRvxvvn1552915529eusmtrp1v; Mon, 26 Nov 2018 14:32:02 +0000 (GMT) X-AuditID: cbfec7f4-84fff700000010c6-d2-5bfc03e3b543 Received: from eusmtip1.samsung.com ( [203.254.199.221]) by eusmgms2.samsung.com (EUCPMTA) with SMTP id B7.DF.04128.2E30CFB5; Mon, 26 Nov 2018 14:32:02 +0000 (GMT) Received: from [106.109.129.180] (unknown [106.109.129.180]) by eusmtip1.samsung.com (KnoxPortal) with ESMTPA id 20181126143202eusmtip1cb27452c60b2b918a76f49094145119c~qsxRXg_G82764827648eusmtip1i; Mon, 26 Nov 2018 14:32:02 +0000 (GMT) To: "Burakov, Anatoly" , Asaf Sinai , "dev@dpdk.org" , Thomas Monjalon From: Ilya Maximets Message-ID: <7868b0b5-d4f5-9e64-ec55-f7bbdc45b400@samsung.com> Date: Mon, 26 Nov 2018 17:32:01 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-GB Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrEKsWRmVeSWpSXmKPExsWy7djPc7qPmf9EG2xdJmHx6N5iZovGA8tZ LN592s5kcaX9J7vFpwcnWBxYPX4tWMrqsXjPSyaPYzensXvc/nie1aNvyyrGANYoLpuU1JzM stQifbsErox79+YzFsw1qdi46BpTA+NTrS5GTg4JAROJgysPs3UxcnEICaxglOi8fJwRwvnC KDF/6hRGkCohgc+MEp+npsJ0tP1qZYEoWs4ose7jHyjnI6PEickdzCCOsMBkRokNSz6ADRYR mMsocfDsCnaQfjYBHYlTq48AzeXg4BWwk/i7WwAkzCKgKjHj3RqwdaICERId91ezgdi8AoIS J2c+YQGxOQVsJR7uXw1mMwuISzR9WckKYctLNG+dDbZYQmAeu8S9ixPYIW51kXi5rJsVwhaW eHV8C1RcRuL05B4WCLte4n7LS0aI5g5GiemH/jFBJOwltrw+xw5yKLOApsT6XfoQYUeJ1o4d rCBhCQE+iRtvBSFu4JOYtG06M0SYV6KjTQiiWkXi98HlzBC2lMTNd5+hLvCQuL6ynWkCo+Is JF/OQvLZLCSfzUK4YQEjyypG8dTS4tz01GKjvNRyveLE3OLSvHS95PzcTYzAlHP63/EvOxh3 /Uk6xCjAwajEw7vh++9oIdbEsuLK3EOMEhzMSiK8vkuAQrwpiZVVqUX58UWlOanFhxilOViU xHmrGR5ECwmkJ5akZqemFqQWwWSZODilGhgr/jwx3ntu4rE59SdbmrwrFjsu5vRrWvv0tHVu meGFuqyCulZLJ4X0M/+e78h4IToxObbUwqxx/g1B/ngPPYvATcE8TeYr7IwWuK+/eauoytaK g6N+52Gp+l/7IyrWL5u0qfyEwio95a6wD3s/ek9R/zBp7mkLF0cV72yhdx3pF6V7v76b7qzE UpyRaKjFXFScCADNm1ijNQMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrFIsWRmVeSWpSXmKPExsVy+t/xu7qPmP9EG5xboGbx6N5iZovGA8tZ LN592s5kcaX9J7vFpwcnWBxYPX4tWMrqsXjPSyaPYzensXvc/nie1aNvyyrGANYoPZui/NKS VIWM/OISW6VoQwsjPUNLCz0jE0s9Q2PzWCsjUyV9O5uU1JzMstQifbsEvYx79+YzFsw1qdi4 6BpTA+NTrS5GTg4JAROJtl+tLF2MXBxCAksZJRadncYMkZCS+PHrAiuELSzx51oXG0TRe0aJ ln9XmEEcYYHJjBLPt08Fy4gIzGWUmDmniRWibDWrxNEn28D62QR0JE6tPsLYxcjBwStgJ/F3 twBImEVAVWLGuzWMILaoQITE2ZfrwGxeAUGJkzOfsIDYnAK2Eg/3rwazmQXUJf7Mu8QMYYtL NH1ZyQphy0s0b53NPIFRcBaS9llIWmYhaZmFpGUBI8sqRpHU0uLc9NxiI73ixNzi0rx0veT8 3E2MwHjaduznlh2MXe+CDzEKcDAq8fBu+P47Wog1say4MvcQowQHs5IIr+8SoBBvSmJlVWpR fnxRaU5q8SFGU6DnJjJLiSbnA2M9ryTe0NTQ3MLS0NzY3NjMQkmc97xBZZSQQHpiSWp2ampB ahFMHxMHp1QDo+SR2FJJtWyHuSWJB8R8z77ft+LwrbcNNc4/DTgZm67Neivy0/7Iuu91G2d7 2q1dcPzV059pVo1PRKvcd4U1iNia58x6Iai0/1zVhFIf34qu6253N4epf7tZ66q1WOmz8h5W w0cp2i6KV3MTkkpCpDm3bK9y/nitqZ/DIOH5h8JzrWs/Nb7KVWIpzkg01GIuKk4EACufJFe9 AgAA X-CMS-MailID: 20181126143202eucas1p2c8387dc0bbb3f6e0623b3b545e23d299 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20181126125108epcas1p2c649d8fa87fb739c2f13435e5ba80d88 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20181126125108epcas1p2c649d8fa87fb739c2f13435e5ba80d88 References: <2b09cec8-0883-2ed2-0264-aeef871ea6a9@intel.com> <518f9333-8d80-0fa2-d391-b4c8df181508@intel.com> <12283bd1-ea0d-38d1-f64d-508596e48cd9@intel.com> <6ce31b20-19ea-ccaf-17d4-f36ab3959710@samsung.com> <5a045a4f-4037-cebf-ea02-7018c28918d0@samsung.com> <7edc7b3b-4a35-3b90-a10a-de67e7f31261@intel.com> Subject: Re: [dpdk-dev] CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES: no difference in memory pool allocations, when enabling/disabling this configuration 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: , X-List-Received-Date: Mon, 26 Nov 2018 14:32:05 -0000 On 26.11.2018 17:21, Burakov, Anatoly wrote: > On 26-Nov-18 2:10 PM, Ilya Maximets wrote: >> On 26.11.2018 16:42, Burakov, Anatoly wrote: >>> On 26-Nov-18 1:20 PM, Ilya Maximets wrote: >>>> On 26.11.2018 16:16, Ilya Maximets wrote: >>>>> On 26.11.2018 15:50, Burakov, Anatoly wrote: >>>>>> On 26-Nov-18 11:43 AM, Burakov, Anatoly wrote: >>>>>>> On 26-Nov-18 11:33 AM, Asaf Sinai wrote: >>>>>>>> Hi Anatoly, >>>>>>>> >>>>>>>> We did not check it with "testpmd", only with our application. >>>>>>>>    From the beginning, we did not enable this configuration (look at attached files), and everything works fine. >>>>>>>> Of course we rebuild DPDK, when we change configuration. >>>>>>>> Please note that we use DPDK 17.11.3, maybe this is why it works fine? >>>>>>> >>>>>>> Just tested with DPDK 17.11, and yes, it does work the way you are describing. This is not intended behavior. I will look into it. >>>>>>> >>>>>> >>>>>> +CC author of commit introducing CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES. >>>>>> >>>>>> Looking at the code, i think this config option needs to be reworked and we should clarify what we mean by this option. It appears that i've misunderstood what this option actually intended to do, and i also think it's naming could be improved because it's confusing and misleading. >>>>>> >>>>>> In 17.11, this option does *not* prevent EAL from using NUMA - it merely disables using libnuma to perform memory allocation. This looks like intended (if counter-intuitive) behavior - disabling this option will simply revert DPDK to working as it did before this option was introduced (i.e. best-effort allocation). This is why your code still works - because EAL still does allocate memory on socket 1, and *knows* that it's socket 1 memory. It still supports NUMA. >>>>>> >>>>>> The commit message for these changes states that the actual purpose of this option is to enable "balanced" hugepage allocation. In case of cgroups limitations, previously, DPDK would've exhausted all hugepages on master core's socket before attempting to allocate from other sockets, but by the time we've reached cgroups limits on numbers of hugepages, we might not have reached socket 1 and thus missed out on the pages we could've allocated, but didn't. Using libnuma solves this issue, because now we can allocate pages on sockets we want, instead of hoping we won't run out of hugepages before we get the memory we need. >>>>>> >>>>>> In 18.05 onwards, this option works differently (and arguably wrong). More specifically, it disallows allocations on sockets other than 0, and it also makes it so that EAL does not check which socket the memory *actually* came from. So, not only allocating memory from socket 1 is disabled, but allocating from socket 0 may even get you memory from socket 1! >>>>> >>>>> I'd consider this as a bug. >>>>> >>>>>> >>>>>> +CC Thomas >>>>>> >>>>>> The CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES option is a misnomer, because it makes it seem like this option disables NUMA support, which is not the case. >>>>>> >>>>>> I would also argue that it is not relevant to 18.05+ memory subsystem, and should only work in legacy mode, because it is *impossible* to make it work right in the new memory subsystem, and here's why: >>>>>> >>>>>> Without libnuma, we have no way of "asking" the kernel to allocate a hugepage on a specific socket - instead, any allocation will most likely happen on socket from which the allocation came from. For example, if user program's lcore is on socket 1, allocation on socket 0 will actually allocate a page on socket 1. >>>>>> >>>>>> If we don't check for page's NUMA node affinity (which is what currently happens) - we get performance degradation because we may unintentionally allocate memory on wrong NUMA node. If we do check for this - then allocation of memory on socket 1 from lcore on socket 0 will almost never succeed, because kernel will always give us pages on socket 0. >>>>>> >>>>>> Put it simply, there is no sane way to make this option work for the new memory subsystem - IMO it should be dropped, and libnuma should be made a hard dependency on Linux. >>>>> >>>>> I agree that new memory model could not work without libnuma, i.e. will >>>>> lead to unpredictable memory allocations with no any respect to requested >>>>> socket_id's. I also agree that CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES is only >>>>> sane for a legacy memory model. >>>>> It looks like we have no other choice than just drop the option and make >>>>> the code unconditional, i.e. have hard dependency on libnuma. >>>>> >>>> >>>> We, probably, could compile this code and have hard dependency only for >>>> platforms with 'RTE_MAX_NUMA_NODES > 1'. >>> >>> Well, as long as legacy mode stays supported, we have to keep the option. The "drop" part was referring to supporting it under the new memory system, not a literal drop from config files. >> >> The option was introduced because we didn't want to introduce the >> new hard dependency. Since we'll have it anyway, I'm not sure if >> keeping the option for legacy mode makes any sense. > > Oh yes, you're right. Drop it is! > >> >>> >>> As for using RTE_MAX_NUMA_NODES, i don't think it's merited. Distributions cannot deliver different DPDK versions based on the number of sockets on a particular machine - so it would have to be a hard dependency for distributions anyway (does any distribution ship DPDK without libnuma?). >> >> At least ARMv7 builds commonly does not ship libnuma package. > > Do you mean libnuma builds for ARMv7 are not available? Or do you mean the libnuma package is not installed by default? > > If it's the latter, then i believe it's not installed by default anywhere, but if using distribution version of DPDK, libnuma will be taken care of via package manager. Presumably building from source can be taken care of with pkg-config/meson. > > Or do you mean ARMv7 does not have libnuma for their arch at all, in any distro? libnuma builds for ARMv7 are not available in most of the distros. I didn't check all, but here is results for Ubuntu: https://packages.ubuntu.com/search?suite=bionic&arch=armhf&searchon=names&keywords=libnuma You may see that Ubuntu 18.04 (bionic) has no libnuma package for 'armhf' and also 'powerpc' platforms. > >> >>> >>> For those compiling from source - are there any supported distributions which don't package libnuma? I don't see much sense in keeping libnuma optional, IMO. This is of course up to the tech board to decide, but IMO the "without libnuma it's basically broken" argument is very strong in my opinion :) >>> >> > >