Re: [PATCH v2 00/17] net: introduce Qualcomm IPA driver (UPDATED)

From: Alex Elder <elder@linaro.org>
To: Dave Taht <dave.taht@gmail.com>
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
Subject: Re: [PATCH v2 00/17] net: introduce Qualcomm IPA driver (UPDATED)
Date: Wed, 11 Mar 2020 22:09:56 -0500	[thread overview]
Message-ID: <e4f436b4-3dd7-970a-9b08-7601fc5428d2@linaro.org> (raw)
In-Reply-To: <CAA93jw5enz6-h1m=7tGFToK+E+8z3aD80pBef4AYkFrS2u3hHQ@mail.gmail.com>

On 3/9/20 11:54 AM, Dave Taht wrote:
> 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?

There exists some hardware that could be used, but at the moment I have
not ported this code to operate on it.  It is a current effort however,
and I will be glad to keep you in the loop on progress.  There are a
couple of target environments we'd like to support but until last week
the primary goal was inclusion in the upstream tree.

I will follow up with you after the dust settles a little bit with
this patch series, maybe in a week or so.  In the mean time I'll
also find out whether there are any other resources (people and/or
hardware) available.

					-Alex