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 97DB8A0542; Wed, 15 Jul 2020 11:48:06 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id E1CFE1BF6D; Wed, 15 Jul 2020 11:48:04 +0200 (CEST) Received: from out2-smtp.messagingengine.com (out2-smtp.messagingengine.com [66.111.4.26]) by dpdk.org (Postfix) with ESMTP id 0ACB52BF3 for ; Wed, 15 Jul 2020 11:48:03 +0200 (CEST) Received: from compute7.internal (compute7.nyi.internal [10.202.2.47]) by mailout.nyi.internal (Postfix) with ESMTP id 359A15C0068; Wed, 15 Jul 2020 05:48:02 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute7.internal (MEProxy); Wed, 15 Jul 2020 05:48:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=monjalon.net; h= from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding:content-type; s=fm1; bh= 0YjqEcKr1M8z5b0j89dq0Jwow8knz8dKm4Q/c8Sj9O8=; b=di1s9n2v52VGy8WX DKXbpbJaNOa6dyPEEqVGDUAQgMtcV3KI8br+JZABEnwC0lJf3p0myiNGQ7ONG2S3 DT+9JC+0N6teVVbtzkiYYljMe//c96o60bGxkueqpt9e76Ni9cD2IoDendzncH84 PJag+pYcQNt04Lhy6eLh0pUR3mfPcqbHle2T96utIm5CG0vhEo3QYiKNjxI/tVDN khr2Xj+htaSbsAAyjU24RoqpkA2u5TgIVHMcpXfcP8W5g72XMbPYG1d21qC4xpmm b7/9WVFfBuN/wwAGxZbibx7/xtlGexRPviebiU7+UgNpphdyxUTDcDwBlHhr9+zh YsiLxw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm3; bh=0YjqEcKr1M8z5b0j89dq0Jwow8knz8dKm4Q/c8Sj9 O8=; b=aVre/gt4QaztO3dTm9WLJWOZop8pQYiqQFpraSbaLju6T2BDTTfCkstc4 aV7T8V49WuSXZwfpwQEle6XKubf8llLxj9dE/Akn9SAxOzRGYIfCQk585KtNmFSG ZzSg2Rwa91DeYP2+6LF8cPD25/Hv6x7eb3dHTdqxVvro8A0mhECEXj/4JajPcqzC V0dURz+7mdbJLq/UwU67zVEiDgkGu2U0SFYFz3T4QTbypcwRC/EPE7kqQJGyEXo8 pk9QG7KRRQOIp6O54iUk5VT2BfjrR4DZlvgnhcxqcE2ekZGu0LffTSX+MgWyVNkT hndRsmlnZUtGGMYSnQJd2kPU/+jyw== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduiedrfedvgddvvdcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpefhvffufffkjghfggfgtgesthfuredttddtvdenucfhrhhomhepvfhhohhmrghs ucfoohhnjhgrlhhonhcuoehthhhomhgrshesmhhonhhjrghlohhnrdhnvghtqeenucggtf frrghtthgvrhhnpedugefgvdefudfftdefgeelgffhueekgfffhfeujedtteeutdejueei iedvffegheenucfkphepjeejrddufeegrddvtdefrddukeegnecuvehluhhsthgvrhfuih iivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepthhhohhmrghssehmohhnjhgrlhho nhdrnhgvth X-ME-Proxy: Received: from xps.localnet (184.203.134.77.rev.sfr.net [77.134.203.184]) by mail.messagingengine.com (Postfix) with ESMTPA id 431E530600B9; Wed, 15 Jul 2020 05:48:00 -0400 (EDT) From: Thomas Monjalon To: "Kinsella, Ray" , Stephen Hemminger Cc: Vladimir Medvedkin , dev@dpdk.org, david.marchand@redhat.com, jerinj@marvell.com, konstantin.ananyev@intel.com, bruce.richardson@intel.com Date: Wed, 15 Jul 2020 11:47:59 +0200 Message-ID: <1758703.2oNzlfH3Ak@thomas> In-Reply-To: <20200714073828.7cdd7355@hermes.lan> References: <98d800b4-41f8-751d-c1a5-5365135c225e@ashroe.eu> <20200714073828.7cdd7355@hermes.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH v6 0/8] fib: implement AVX512 vector lookup 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" 14/07/2020 16:38, Stephen Hemminger: > "Kinsella, Ray" wrote: > > On 13/07/2020 23:19, Stephen Hemminger wrote: > > > Did anyone else see the recent AVX512 discussion from Linus: > > > "I hope AVX512 dies a painful death, and that Intel starts fixing real problems > > > instead of trying to create magic instructions to then create benchmarks that they can look good on. > > > > Yup - I saw this one. > > Sweeping statements like these are good to provoke debate, the truth is generally more nuanced. > > If you continue to read the post, Linus appears to be mostly questioning microprocessor design decisions. > > > > That is an interesting discussion, however the reality is that the technology does exists and may be beneficial for Packet Processing. > > > > I would suggest, we continue to apply the same logic governing adoption of any technology by DPDK. > > When the technology is present and a clear benefit is shown, we use it with caution. > > > > In the case of Vladimir's patch, > > the user has to explicitly switch on the AVX512 lookup with RTE_FIB_DIR24_8_VECTOR_AVX512. > > Using what is available makes sense in DPDK. Why does it require explicit enabling in application? AVX512 is not reliable enough to be automatically used when available?