New subject: .git submodules increase hafnium code size

31 May 2021


      Hi Varun,
We had similar requests raised internally.
1- First in context of Total Compute delivery from Arm OSS platforms:
    a. ability to build only the SPMC on TC0 platform (not all reference targets such as qemu, rpi4, fvp)
    b. use a Yocto provided toolchain.
    @Arun, your view on how those two items were solved is beneficial to further elaborate our plans.
2- A similar request as 1.b to build Hafnium as part of a distribution on arm64 host: https://developer.trustedfirmware.org/T898
In my view there are two consumers: 
-A distribution only requiring the Hypervisor/SPMC output binary ("out/reference/.../hafnium.bin") using any toolchain (be it arm64 or x86 host, and arbitrary clang version).
-The Hf CI framework/automation needs the above, plus the test framework and tests (dependency on googletest, linux submodules etc). It's important to keep this item alive while trying to solve above item.
As you noticed, the Hafnium Hypervisor/SPMC and test environment builds are closely coupled by the use of ninja/gn flow and scripts.
They are using a fixed toolchain version through prebuilts to ensure builds are "reproducible", in particular with regards to the Hafnium CI.
We intend to approach those problems in the course of Q3 in Arm OSS roadmap.
As an early exploration we already have:
-clang 12 compiler upgrade. This is necessary if wiling to use any arbitrary clang version:
https://review.trustedfirmware.org/q/topic:%22od%252Fhf-clang12%22+(status:o...)
-Ability to build on arm64 host (done, internally).
-Identify the flow/script changes such that external dependencies can be used (on-going, internally).
I thought of localizing common dependencies to python/shell scripts by the use of definition files included in the mentioned scripts. This is only an early investigation, I will check how this intersects the changes you provided.
Regards,
Olivier.
From: Hafnium hafnium-bounces@lists.trustedfirmware.org on behalf of Varun Wadekar via Hafnium hafnium@lists.trustedfirmware.org
Sent: 28 May 2021 16:47
To: hafnium@lists.trustedfirmware.org hafnium@lists.trustedfirmware.org
Cc: Bo Yan byan@nvidia.com
Subject: [Hafnium] .git submodules increase hafnium code size 
 
Hi,
We at NVIDIA are evaluating Hafnium. During the initial investigation, we found out that the repository size (in terms of MB) is huge. This is mostly because of the "git submodules" used by the project. This is a great way to deliver Hafnium with its dependencies in one go.
But we think that the size can be trimmed by moving the toolchain, linux folder, googletest and dtc compiler out, leaving just the Hafnium code in the project. This way, companies like us can pick and choose instead of having to use everything. In a bid to ease the pain internally and only use the Hafnium code base we have crafted the following changes:
1.  hafnium: support external projects (I10a07de3) * Gerrit Code Review (trustedfirmware.org)https://review.trustedfirmware.org/c/hafnium/hafnium/+/10142
  2.  hafnium: build with dtc and googletest out of tree (I057c9ad6) * Gerrit Code Review (trustedfirmware.org)https://review.trustedfirmware.org/c/hafnium/hafnium/+/10144
  3.  build: support external toolchain (Iafd029c1) * Gerrit Code Review (trustedfirmware.org)https://review.trustedfirmware.org/c/hafnium/hafnium/+/10145
This series does not have the patch to use an out of tree linux codebase. I assume these patches wont be acceptable in their current state, so would like to know how the community plans to handle this situation.
The code size is a real concern for us, as we already have copies of the dependencies in our codebase, so have no use for these duplicates.
Thanks.
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Re: [Hafnium] .git submodules increase hafnium code size