From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75FF1C4338F for ; Tue, 27 Jul 2021 09:12:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 606556125F for ; Tue, 27 Jul 2021 09:12:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236058AbhG0JMO (ORCPT ); Tue, 27 Jul 2021 05:12:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235981AbhG0JMI (ORCPT ); Tue, 27 Jul 2021 05:12:08 -0400 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C433C061760 for ; Tue, 27 Jul 2021 02:12:06 -0700 (PDT) Received: by mail-pl1-x631.google.com with SMTP id d17so15006695plh.10 for ; Tue, 27 Jul 2021 02:12:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=9rluK+pOhIb8FILDrgZN4MclSo9wi1R9TyuuYegFS3c=; b=O8RNZOylgIfFd5MJB6bCTVdF9M+YC3fNptlBHMCtVio314rf3eWtCfGWIGhQV5q4tw wPuKCyTFlHtgAoX9G/xJlIjgDaq8SyuKQ/OfClRzWJZe6FYm0drviLCKPGBOx7WD5jHM IcblQ3zfH9PfEUKyzdnpf3wSqpKS7M8dKN+zWYhOujSLbKwjB4zjuShC3cEOF+l24NUf bUm4S8vnqIZ4FNtZOs569hu77icxuZRMfa8kL6SGsPa6joINB9gDvv0tIkJLKpDwfX1t kQrJ8XwDr627CliLCTFbVa+4wozAmCt9kyCApFh+aV/3XgedL7tlQjJ3KlqQbuzbxFOP f62g== 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=9rluK+pOhIb8FILDrgZN4MclSo9wi1R9TyuuYegFS3c=; b=DTbpwx23I9f0hhU0az0gEISEsVAMBmRdVY8wQWEvbrfH71UBgaiqSwLap6V8PG/HJP zyB0531HFPS4bBmv5z1Acql+HLTXO8fU/c+9vgkqf2oAcxIw002jOm6e5hHTITxNvSjG Ap7SwW3uqmy0GbYSuJOodAFWM4KmMp5lA0J+qkh+za0831qGNClGJSGA7CIrIA5pHohb jwaFdWDDP0KvjTjZ5N/ltKUWrZ/EoBW+of6Ls4OPC1VxHlKWkhWr1hEEWI5tT/OXoD6F g2kevGDI7A/sXOvDvBGNIk1zH83lEVZXTY0fj/hZ1WxMu9W2Tojd40hja4t3OncxwSCG uF7w== X-Gm-Message-State: AOAM531Nc6B7QGFSw4glxxjHgOK/aRwftgZpmkZVdyBK1gDuJEzuEpZR 2avVWaNiLRaxfAXXMP7g4YjzuCuM7YYAsmqtuKPcmeKTtlZThw== X-Google-Smtp-Source: ABdhPJw2EKqlRylpPbp9OkXdj7y3BeX7ygqlaMweZ8bIg/J3FA1oS1bRlPVBYElNVJbV8Iv4ya+imTT0SW6KULLALUQ= X-Received: by 2002:a62:d447:0:b029:291:19f7:ddcd with SMTP id u7-20020a62d4470000b029029119f7ddcdmr22329027pfl.54.1627377125991; Tue, 27 Jul 2021 02:12:05 -0700 (PDT) MIME-Version: 1.0 References: <20210714211805.22350-1-richard.laing@alliedtelesis.co.nz> <5165a859-1b00-e50e-985e-25044cf0e9ec@alliedtelesis.co.nz> In-Reply-To: <5165a859-1b00-e50e-985e-25044cf0e9ec@alliedtelesis.co.nz> From: Loic Poulain Date: Tue, 27 Jul 2021 11:21:52 +0200 Message-ID: Subject: Re: [PATCH] bus: mhi: pci-generic: configurable network interface MRU To: Richard Laing Cc: David Miller , Network Development , open list Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 19 Jul 2021 at 23:44, Richard Laing wrote: > > Hi Loic, > > On 7/19/21 10:11 PM, Loic Poulain wrote: > > For my interest do you have some numbers here highlighting improvement? > These are some of the numbers we found from initial testing using an > external packet generator: > > packet size packets sent throughput (%pps) > 64 1000000 6.21% > 128 1000000 7.42% > 256 1000000 10.79% > 512 1000000 16.40% > 1024 1000000 34.34% > 1262 1000000 43.82% > 1263 1000000 22.45% <-- > 1280 1000000 23.15% > 1500 1000000 46.32% > 1518 1000000 46.84% > > You can see the sudden drop of almost 50% between 1262 and 1263 byte > packets. This is what caused us to investigate further. Following the > change to 32KB buffers the drop in throughput is no longer seen. > > packet size packets sent throughput (%pps) > 64 1000000 4.41% > 128 1000000 7.70% > 256 1000000 14.26% > 512 1000000 27.06% > 1024 1000000 49.39% > 1280 1000000 58.82% > 1428 1000000 62.63% > > In all cases we were testing with the modem itself in internal loopback > mode. > > We have noted that our modem defaults to 32KB buffers (and a maximum of > 32 packets per buffer) and also that these values can be changed. We are > considering adding the ability to tune the buffer size, perhaps adding a > sysfs entry or netlink message to change the buffer size instead of the > hard coded value. Any comments would be appreciated. Thanks for the info, that's interesting. Note that the default MRU you define is not MHI controller specific but MHI channel specific (IP/MBIM channel), so it should not be a property of the MHI controller. AFAIK, The MHI specification already defines MRU for the transfered buffers which is 65535. I would recommend to move this prop to the channel config. Regards, Loic > > Regards, > Richard > > >