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 C7C92A00BE; Tue, 28 Apr 2020 16:50:39 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 2FC601D5F8; Tue, 28 Apr 2020 16:50:39 +0200 (CEST) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by dpdk.org (Postfix) with ESMTP id EF1DA1D5D0 for ; Tue, 28 Apr 2020 16:50:37 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588085437; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=0iIgkeLX7YOozgT7P5ESwFxEyPFhKJl2uQOKiLKe8A0=; b=D+qKZI6YX4t/3UEiyIyqBnDmpNlVRakoyEoG0e2DIHsLTss08KcyGqPNVaRw0O4RjCwjMf 8jFy6+4U6sUoJyqn/Pjzx1m2yDAzTHH+MZrddQqar2e1R7Cl80SvVxPjIDvJxc6M2XPFen kNJivkRnDBoBm8th8tdlhjUAU9qszbg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-195-FaJNH-vIPvajWKB-DlArOg-1; Tue, 28 Apr 2020 10:50:33 -0400 X-MC-Unique: FaJNH-vIPvajWKB-DlArOg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27331835B40; Tue, 28 Apr 2020 14:50:32 +0000 (UTC) Received: from [10.36.110.26] (unknown [10.36.110.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2396619C58; Tue, 28 Apr 2020 14:50:29 +0000 (UTC) To: "Liu, Yong" , "Ye, Xiaolong" , "Wang, Zhihong" Cc: "dev@dpdk.org" , Honnappa Nagarahalli , "jerinj@marvell.com" References: <20200313174230.74661-1-yong.liu@intel.com> <20200426021943.43158-1-yong.liu@intel.com> <20200426021943.43158-7-yong.liu@intel.com> <672a584a-46d1-c78b-7b21-9ed7bc060814@redhat.com> <86228AFD5BCD8E4EBFD2B90117B5E81E63546D0C@SHSMSX103.ccr.corp.intel.com> <86228AFD5BCD8E4EBFD2B90117B5E81E6354755C@SHSMSX103.ccr.corp.intel.com> <679f4dc1-a4ac-ab1b-a7b1-297d66158820@redhat.com> <86228AFD5BCD8E4EBFD2B90117B5E81E635476DC@SHSMSX103.ccr.corp.intel.com> From: Maxime Coquelin Autocrypt: addr=maxime.coquelin@redhat.com; keydata= mQINBFOEQQIBEADjNLYZZqghYuWv1nlLisptPJp+TSxE/KuP7x47e1Gr5/oMDJ1OKNG8rlNg kLgBQUki3voWhUbMb69ybqdMUHOl21DGCj0BTU3lXwapYXOAnsh8q6RRM+deUpasyT+Jvf3a gU35dgZcomRh5HPmKMU4KfeA38cVUebsFec1HuJAWzOb/UdtQkYyZR4rbzw8SbsOemtMtwOx YdXodneQD7KuRU9IhJKiEfipwqk2pufm2VSGl570l5ANyWMA/XADNhcEXhpkZ1Iwj3TWO7XR uH4xfvPl8nBsLo/EbEI7fbuUULcAnHfowQslPUm6/yaGv6cT5160SPXT1t8U9QDO6aTSo59N jH519JS8oeKZB1n1eLDslCfBpIpWkW8ZElGkOGWAN0vmpLfdyiqBNNyS3eGAfMkJ6b1A24un /TKc6j2QxM0QK4yZGfAxDxtvDv9LFXec8ENJYsbiR6WHRHq7wXl/n8guyh5AuBNQ3LIK44x0 KjGXP1FJkUhUuruGyZsMrDLBRHYi+hhDAgRjqHgoXi5XGETA1PAiNBNnQwMf5aubt+mE2Q5r qLNTgwSo2dpTU3+mJ3y3KlsIfoaxYI7XNsPRXGnZi4hbxmeb2NSXgdCXhX3nELUNYm4ArKBP LugOIT/zRwk0H0+RVwL2zHdMO1Tht1UOFGfOZpvuBF60jhMzbQARAQABtCxNYXhpbWUgQ29x dWVsaW4gPG1heGltZS5jb3F1ZWxpbkByZWRoYXQuY29tPokCOAQTAQIAIgUCV3u/5QIbAwYL CQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQyjiNKEaHD4ma2g/+P+Hg9WkONPaY1J4AR7Uf kBneosS4NO3CRy0x4WYmUSLYMLx1I3VH6SVjqZ6uBoYy6Fs6TbF6SHNc7QbB6Qjo3neqnQR1 71Ua1MFvIob8vUEl3jAR/+oaE1UJKrxjWztpppQTukIk4oJOmXbL0nj3d8dA2QgHdTyttZ1H xzZJWWz6vqxCrUqHU7RSH9iWg9R2iuTzii4/vk1oi4Qz7y/q8ONOq6ffOy/t5xSZOMtZCspu Mll2Szzpc/trFO0pLH4LZZfz/nXh2uuUbk8qRIJBIjZH3ZQfACffgfNefLe2PxMqJZ8mFJXc RQO0ONZvwoOoHL6CcnFZp2i0P5ddduzwPdGsPq1bnIXnZqJSl3dUfh3xG5ArkliZ/++zGF1O wvpGvpIuOgLqjyCNNRoR7cP7y8F24gWE/HqJBXs1qzdj/5Hr68NVPV1Tu/l2D1KMOcL5sOrz 2jLXauqDWn1Okk9hkXAP7+0Cmi6QwAPuBT3i6t2e8UdtMtCE4sLesWS/XohnSFFscZR6Vaf3 gKdWiJ/fW64L6b9gjkWtHd4jAJBAIAx1JM6xcA1xMbAFsD8gA2oDBWogHGYcScY/4riDNKXi lw92d6IEHnSf6y7KJCKq8F+Jrj2BwRJiFKTJ6ChbOpyyR6nGTckzsLgday2KxBIyuh4w+hMq TGDSp2rmWGJjASq5Ag0EVPSbkwEQAMkaNc084Qvql+XW+wcUIY+Dn9A2D1gMr2BVwdSfVDN7 0ZYxo9PvSkzh6eQmnZNQtl8WSHl3VG3IEDQzsMQ2ftZn2sxjcCadexrQQv3Lu60Tgj7YVYRM H+fLYt9W5YuWduJ+FPLbjIKynBf6JCRMWr75QAOhhhaI0tsie3eDsKQBA0w7WCuPiZiheJaL 4MDe9hcH4rM3ybnRW7K2dLszWNhHVoYSFlZGYh+MGpuODeQKDS035+4H2rEWgg+iaOwqD7bg CQXwTZ1kSrm8NxIRVD3MBtzp9SZdUHLfmBl/tLVwDSZvHZhhvJHC6Lj6VL4jPXF5K2+Nn/Su CQmEBisOmwnXZhhu8ulAZ7S2tcl94DCo60ReheDoPBU8PR2TLg8rS5f9w6mLYarvQWL7cDtT d2eX3Z6TggfNINr/RTFrrAd7NHl5h3OnlXj7PQ1f0kfufduOeCQddJN4gsQfxo/qvWVB7PaE 1WTIggPmWS+Xxijk7xG6x9McTdmGhYaPZBpAxewK8ypl5+yubVsE9yOOhKMVo9DoVCjh5To5 aph7CQWfQsV7cd9PfSJjI2lXI0dhEXhQ7lRCFpf3V3mD6CyrhpcJpV6XVGjxJvGUale7+IOp sQIbPKUHpB2F+ZUPWds9yyVxGwDxD8WLqKKy0WLIjkkSsOb9UBNzgRyzrEC9lgQ/ABEBAAGJ Ah8EGAECAAkFAlT0m5MCGwwACgkQyjiNKEaHD4nU8hAAtt0xFJAy0sOWqSmyxTc7FUcX+pbD KVyPlpl6urKKMk1XtVMUPuae/+UwvIt0urk1mXi6DnrAN50TmQqvdjcPTQ6uoZ8zjgGeASZg jj0/bJGhgUr9U7oG7Hh2F8vzpOqZrdd65MRkxmc7bWj1k81tOU2woR/Gy8xLzi0k0KUa8ueB iYOcZcIGTcs9CssVwQjYaXRoeT65LJnTxYZif2pfNxfINFzCGw42s3EtZFteczClKcVSJ1+L +QUY/J24x0/ocQX/M1PwtZbB4c/2Pg/t5FS+s6UB1Ce08xsJDcwyOPIH6O3tccZuriHgvqKP yKz/Ble76+NFlTK1mpUlfM7PVhD5XzrDUEHWRTeTJSvJ8TIPL4uyfzhjHhlkCU0mw7Pscyxn DE8G0UYMEaNgaZap8dcGMYH/96EfE5s/nTX0M6MXV0yots7U2BDb4soLCxLOJz4tAFDtNFtA wLBhXRSvWhdBJZiig/9CG3dXmKfi2H+wdUCSvEFHRpgo7GK8/Kh3vGhgKmnnxhl8ACBaGy9n fxjSxjSO6rj4/MeenmlJw1yebzkX8ZmaSi8BHe+n6jTGEFNrbiOdWpJgc5yHIZZnwXaW54QT UhhSjDL1rV2B4F28w30jYmlRmm2RdN7iCZfbyP3dvFQTzQ4ySquuPkIGcOOHrvZzxbRjzMx1 Mwqu3GQ= Message-ID: <2c383833-c67f-c1fb-ea3f-c3802b24de79@redhat.com> Date: Tue, 28 Apr 2020 16:50:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <86228AFD5BCD8E4EBFD2B90117B5E81E635476DC@SHSMSX103.ccr.corp.intel.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v10 6/9] net/virtio: add vectorized packed ring Rx path 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 4/28/20 4:43 PM, Liu, Yong wrote: > > >> -----Original Message----- >> From: Maxime Coquelin >> Sent: Tuesday, April 28, 2020 9:46 PM >> To: Liu, Yong ; Ye, Xiaolong ; >> Wang, Zhihong >> Cc: dev@dpdk.org; Honnappa Nagarahalli >> ; jerinj@marvell.com >> Subject: Re: [PATCH v10 6/9] net/virtio: add vectorized packed ring Rx path >> >> >> >> On 4/28/20 3:01 PM, Liu, Yong wrote: >>>>> Maxime, >>>>> Thanks for point it out, it will add extra cache miss in datapath. >>>>> And its impact on performance is around 1% in loopback case. >>>> Ok, thanks for doing the test. I'll try to run some PVP benchmarks >>>> on my side because when doing IO loopback, the cache pressure is >>>> much less important. >>>> >>>>> While benefit of vectorized path will be more than that number. >>>> Ok, but I disagree for two reasons: >>>> 1. You have to keep in mind than non-vectorized is the default and >>>> encouraged mode to use. Indeed, it takes a lot of shortcuts like not >>>> checking header length (so no error stats), etc... >>>> >>> Ok, I will keep non-vectorized same as before. >>> >>>> 2. It's like saying it's OK it degrades by 5% on $CPU_VENDOR_A because >>>> the gain is 20% on $CPU_VENDOR_B. >>>> >>>> In the case we see more degradation in real-world scenario, you might >>>> want to consider using ifdefs to avoid adding padding in the non- >>>> vectorized case, like you did to differentiate Virtio PMD to Virtio-user >>>> PMD in patch 7. >>>> >>> Maxime, >>> The performance difference is so slight, so I ignored for it look like a >> sampling error. >> >> Agree for IO loopback, but it adds one more cache line access per burst, >> which might be see in some real-life use cases. >> >>> It maybe not suitable to add new configuration for such setting which >> only used inside driver. >> >> Wait, the Virtio-user #ifdef is based on the defconfig options? How can >> it work since both Virtio PMD and Virtio-user PMD can be selected at the >> same time? >> >> I thought it was a define set before the headers inclusion and unset >> afterwards, but I didn't checked carefully. >> > > Maxime, > The difference between virtio PMD and Virtio-user PMD addresses is handled by vq->offset. > > When virtio PMD is running, offset will be set to buf_iova. > vq->offset = offsetof(struct rte_mbuf, buf_iova); > > When virtio_user PMD is running, offset will be set to buf_addr. > vq->offset = offsetof(struct rte_mbuf, buf_addr); Ok, but below is a build time check: +#ifdef RTE_VIRTIO_USER + __m128i flag_offset = _mm_set_epi64x(flags_temp, (uint64_t)vq->offset); +#else + __m128i flag_offset = _mm_set_epi64x(flags_temp, 0); +#endif So how can it work for a single build for both Virtio and Virtio-user? >>> Virtio driver can check whether virtqueue is using vectorized path when >> initialization, will use padded structure if it is. >>> I have added some tested code and now performance came back. Since >> code has changed in initialization process, it need some time for regression >> check. >> >> Ok, works for me. >> >> I am investigating a linkage issue with your series, which does not >> happen systematically (see below, it happens also with clang). David >> pointed me to some Intel patches removing the usage if __rte_weak, >> could it be related? >> > > I checked David's patch, it only changed i40e driver. Meanwhile attribute __rte_weak should still be in virtio_rxtx.c. > I will follow David's patch, eliminate the usage of weak attribute. Yeah, I meant below issue could be linked to __rte_weak, not that i40e patch was the cause of this problem.