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From:   Dave Taht <dave.taht@gmail.com>
Date:   Mon, 9 Mar 2020 09:54:42 -0700
Message-ID: <CAA93jw5enz6-h1m=7tGFToK+E+8z3aD80pBef4AYkFrS2u3hHQ@mail.gmail.com>
Subject: Re: [PATCH v2 00/17] net: introduce Qualcomm IPA driver (UPDATED)
To:     Alex Elder <elder@linaro.org>
Cc:     David Miller <davem@davemloft.net>, Arnd Bergmann <arnd@arndb.de>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Johannes Berg <johannes@sipsolutions.net>,
        Dan Williams <dcbw@redhat.com>,
        Evan Green <evgreen@google.com>,
        Eric Caruso <ejcaruso@google.com>,
        Susheel Yadav Yadagiri <syadagir@codeaurora.org>,
        Chaitanya Pratapa <cpratapa@codeaurora.org>,
        Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Siddharth Gupta <sidgup@codeaurora.org>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        devicetree@vger.kernel.org,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org
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I am happy to see this driver upstream.

>Arnd's concern was that the rmnet_data0 network device does not
>have the benefit of information about the state of the underlying
>IPA hardware in order to be effective in controlling TX flow.
>The feared result is over-buffering of TX packets (bufferbloat).
>I began working on some simple experiments to see whether (or how
>much) his concern was warranted.  But it turned out that completing
>these experiments was much more work than had been hoped.

Members of the bufferbloat project *care*, and have tools and testbeds for
exploring these issues. It would be good to establish a relationship with
the vendor, obtain hardware, and other (technical and financial) support, if
possible.

Is there any specific hardware now available (generally or in beta) that
can be obtained by us to take a harder look? A contact at linaro or QCA
willing discuss options?