Thanks, Madhukar.

I think this needs a broader discussion where we form a list evaluation criteria of features, API, metrics, KPIs etc by pooling them from the platform owners.

If we don’t receive any inputs, then it makes sense to execute the current tests and make sure that they work as expected.

Thoughts?

-Varun

From: Madhukar Pappireddy <Madhukar.Pappireddy@arm.com>
Sent: Monday, June 15, 2020 8:30 AM
To: Varun Wadekar <vwadekar@nvidia.com>
Cc: tf-a@lists.trustedfirmware.org
Subject: RE: Upgrading libfdt library

External email: Use caution opening links or attachments

Hi Varun,

Please find my replies inline.

Thanks,

Madhu

From: Varun Wadekar <vwadekar@nvidia.com>
Sent: Friday, June 12, 2020 7:04 PM
To: Madhukar Pappireddy <Madhukar.Pappireddy@arm.com>
Cc: tf-a@lists.trustedfirmware.org
Subject: RE: Upgrading libfdt library

Hi Madhukar,

Before we merge this change, can you please explain how we arrived at this specific version? Are we tracking the stable version of the library?

>> I was told by Andre that the releases(tags) by themselves don’t mean much in the libfdt project and it is better to upgrade directly to the recent commit(the latest HEAD was 85e5d83 when I started this investigation).

What would be the testing criteria before merging the library? Does tftf provide any tests that can act as a smoking gun?

>> Given that we rely more on libfdt APIs now, I plan to run all the existing tests in our CI (includes tftf and Linux boot tests) to verify if the libfdt library has any issues when integrating with TF-A. I believe these tests are thorough enough.

Does it make sense to ask platform owners to test the specific version you plan to merge? This way we would have more confidence in the library.

>> Yes, I wanted to take the feedback from platform owners and hence I sent this email before actually pushing the patch to tf.org for review. There was a performance concern in the past when upgrading libfdt source files [1].

[1] https://github.com/ARM-software/tf-issues/issues/643

-Varun

From: TF-A <tf-a-bounces@lists.trustedfirmware.org> On Behalf Of Madhukar Pappireddy via TF-A
Sent: Friday, June 12, 2020 4:48 PM
To: tf-a@lists.trustedfirmware.org
Subject: [TF-A] Upgrading libfdt library

External email: Use caution opening links or attachments

Hello,

I am planning to upgrade libfdt library source files in TF-A. They haven’t been updated for a while. As the project moves towards improving the fconf framework and adding more properties in device tree source files, we rely more on libfdt APIs. I have done some preliminary investigation to check if there is any performance penalty in upgrading the libfdt source files integrated into TF-A  from the current version(which corresponds to commit aadd0b6 in the dtc repo [1]) to master commit (85e5d83). I have run some basics tests on both x86 and aarch64 machines and I have not seen any performance degradation. I plan to push a patch shortly to integrate the latest version of libfdt files in TF-A.

Please let me know if you are aware of any performance issues or have other concerns.

[1] https://git.kernel.org/pub/scm/utils/dtc/dtc.git

Thanks,

Madhu