From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f173.google.com (mail-io0-f173.google.com [209.85.223.173]) by dpdk.org (Postfix) with ESMTP id 8728CA48D for ; Mon, 22 Jan 2018 19:20:53 +0100 (CET) Received: by mail-io0-f173.google.com with SMTP id f34so10387689ioi.13 for ; Mon, 22 Jan 2018 10:20:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=semihalf-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=REpk1spbuNDZgwxD0GpZuaqduSa2I+YzoVcnwa77ppg=; b=wDzLV3r3Ox5IyPCXXKirSemkXCGfLwGBzM10V+VUS1MIqEzffIeSnLly6Fv5mwIApr iaLNeIEqEUeOs4KZTArLawtNRAxKzDu+HdqoikPxrvfqKm4wqweYU3WubdqWDuST24cz whIxSWkWJgCVN4stxyeWmhggs0CjD/TVGMH/BPIUTys6yUq9POzMov/ssOc2FbUKCWS1 cLdm8P/kg4C/VqUz1Sadzn59i5FS85KYiHl/QfzaPgZk7nthlnunEYOlGUyIYfik/DLv gJdU3gR4zYEBsHwHkwALGplG0Y+oqX+O5tPVIf2DoNUhU6wLhr1TKBNuzv9RJwf+5xwY 5jLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=REpk1spbuNDZgwxD0GpZuaqduSa2I+YzoVcnwa77ppg=; b=XKOMAwKfCgiBPnpLbBNN+/D49Wo6uoPubtBQEPDJ86sfPMZbUPl/jRVn7i9AjxeC/w rPnvT4qkjJsI9TXtOSOAjCJrvzBAs4355xaeqRknJor3qE/31+7dx8DtgB/pYPFyOaha AxO6iNEPFYvmvLFFOEs5cLMOrO+9U4j8ca4NEvkjGgL432Gp3K787FPLYW1zYXVqOHeI tpiaqwfhdE4qmYPSE5Koer+RL2lNPKz5nxzCkzoPE3TahZzDPv5rkhoiqoG9n5wc0LBb iaiuV6QrOZYWvFiyI/XqalbHwWNcFsq/euQob+D23KziUfDK6tpneBPvLvJkBJ5EwaaL rduQ== X-Gm-Message-State: AKwxytct+FOHqukxMtY0g0PeJg//iGrVORgqpUy/GrIKkbNli/UXbO2y CWl4l/0kMBGir1+abLcU59rYe4XBkyt3N5663IiuLA== X-Google-Smtp-Source: AH8x227XSRIWYAL6ksT6DQVEsIROt1BCaUdarbLDul4niC6MS4ZGMRogcHeJ6b0sLH2OkaOCZR0S8IJnsGj9OjJEftA= X-Received: by 10.107.88.19 with SMTP id m19mr9454448iob.113.1516645252879; Mon, 22 Jan 2018 10:20:52 -0800 (PST) MIME-Version: 1.0 Received: by 10.79.209.164 with HTTP; Mon, 22 Jan 2018 10:20:32 -0800 (PST) In-Reply-To: References: <16d055c21f6c9e3788fff1a9ecef12d1449d7305.1516373253.git.aber@semihalf.com> From: Andriy Berestovskyy Date: Mon, 22 Jan 2018 19:20:32 +0100 Message-ID: To: "Van Haaren, Harry" Cc: "dev@dpdk.org" , "Horton, Remy" Content-Type: text/plain; charset="UTF-8" Subject: Re: [dpdk-dev] [PATCH] keepalive: fix keepalive state alignment 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, 22 Jan 2018 18:20:53 -0000 Hey Harry, Thanks for the review. On Fri, Jan 19, 2018 at 6:31 PM, Van Haaren, Harry wrote: > These changes do reduce false-sharing however is there actually a performance benefit? A lot of cache space will be taken up if each core requires its own cache line, which will reduce performance again.. it's a tradeoff. 1. False sharing is happening in the data path vs loops in control paths. 2. The original code (prior e70a61ad50ab "keepalive: export states") had each element aligned to the cache line, not the whole array. > Little fix for a v2: "s" is not a good variable name for the rte_keepalive_state, please use something more descriptive. Sure, if there are no more comments, I'll change it. Andriy