From owner-freebsd-net@freebsd.org Sat Dec 2 06:04:56 2017 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 5F3C3DF4A60 for ; Sat, 2 Dec 2017 06:04:56 +0000 (UTC) (envelope-from kmacybsd@gmail.com) Received: from mail-oi0-f53.google.com (mail-oi0-f53.google.com [209.85.218.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 323473034 for ; Sat, 2 Dec 2017 06:04:55 +0000 (UTC) (envelope-from kmacybsd@gmail.com) Received: by mail-oi0-f53.google.com with SMTP id s9so8588032oie.5 for ; Fri, 01 Dec 2017 22:04:55 -0800 (PST) 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=XDNnhVI5Xe3e7Z9MfvLl5L0OI0U2d56vIIsGFwNH/uo=; b=Do24QKvmgg4aFZIjDNWCU2wKj/8/SSTR6ucCiQb45sEWIELOBNX9Wxk6G9UoXaZTbh Gs1xyqTXkAilSBjqE6ySmdNVMMTO6bzbRVbv6d4ZuD76nIcbyK/r0ejyvKGg75FJzkBM nXzraYdJVHCMjZuynavmNPnpac7K0UE+kNPW0l8lJR/W6Lyy89Tj/rfdoIExWTKddIpW MGvNf8XjrUNF4ThamRM4mhiLCGCSARdJ6ubHc0Cgn082yr3lG38dIBXvIdRMoXP18qf7 Ws20TcEh8pl+XxHps/3rII74PTZvmyyTv3esgvaMKoxbsYaipcAN/h7PVyavlRL8aV7I rHsA== X-Gm-Message-State: AJaThX4lNHTZ9lYN7ObUpDthQZlDe2ZuAP60IYAmU1LlYc7PpX2t14d2 /717FoRIOAXM40oZEwZllx4f57lH7hsU6IRaoZE= X-Google-Smtp-Source: AGs4zMZSKkFN3tz44u2ccYacgUiATS9/SYNLC9FAwjgGmz7BA2UTVer+BdkVAja4j1it2LOiGq3mWjgU8CWa/+g4OE0= X-Received: by 10.202.8.216 with SMTP id 207mr9140594oii.334.1512191490825; Fri, 01 Dec 2017 21:11:30 -0800 (PST) MIME-Version: 1.0 References: <5A206FB9.3010106@cox.net> In-Reply-To: <5A206FB9.3010106@cox.net> From: "K. Macy" Date: Sat, 02 Dec 2017 05:11:20 +0000 Message-ID: Subject: Re: netmap / LINUX realtime / ixgbevf: huge RX latencies To: Joe Buehler Cc: "freebsd-net@freebsd.org" Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.25 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 02 Dec 2017 06:04:56 -0000 HEAD or 11? On Thu, Nov 30, 2017 at 13:03 Joe Buehler wrote: > I am using the LINUX 4.4.86 realtime kernel patch with netmap and the > ixgbevf driver (SRIOV in a VM) and having some serious RX latency issues. > > The ixbgevf driver built by the netmap build against the kernel source > does not work. I haven't tried to debug it -- the netmap driver > complains about bad ring index values and resets (over and over again as > my app runs). > > The non-netmap version of ixgbevf that comes with the kernel works but > appears to have serious RX latency issues due to frame batching. It > appears that the kernel's NAPI polling reads frames from the NIC, then > netmap processes the frames, then epoll exits and my app can work on the > frames. The delay between start of NAPI to my app getting frames can be > milliseconds!!! > > Would the netmap-modified ixgbevf driver eliminate this latency? > > If so, any ideas on what might be going wrong with the modified driver? > Perhaps an older version of the driver might be better? The kernel > ixgbevf version is 2.12.1-k while netmap is trying to use 4.2.1. > Looking at the RT patch for LINUX there are only a few network driver > patches, none for the ixgbe* cards. > > Joe Buehler > > _______________________________________________ > freebsd-net@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >