CryptoAlg-629: Remove prefetch from select_w7 #82
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This improved the performance slightly, thanks @sebpop. Also, addressed other comments from Sebastian on the development application.
Copy/paste mistake placed `ret` before popping the stack.
This change includes reverting "CryptoAlg-530: Add ci test with -DOPENSSL_AARCH64_P256=1" commit [270f803](aws@270f803).
dkostic
approved these changes
Jan 12, 2021
bryce-shang
approved these changes
Jan 12, 2021
dkostic
pushed a commit
to dkostic/aws-lc
that referenced
this pull request
Dec 5, 2024
This patch adds a constant-time table-lookup function for x86 and its proof. This resolves issue aws#82. Also, it contains the following changes: - The specification of Arm bignum_copy_row_from_table is slightly updated to use `LENGTH bignum_copy_row_from_table_mc` rather than its actual number. - `x86_print_log` flag is added, to do the things what `arm_print_log` does. - Let `NONOVERLAPPING_TAC` print the goal when it fails, to help users. Resolving the origin of the problem (dealing with negative offset in nonoverlapping reasoning) was simply avoided by rewriting the relevant loop assembly code from decreasing counter form to increasing counter form. I think this issue must be addressed at some point. For constant-time table lookup, this wasn't a critical problem however. I have an idea for reducing the time that proof CI takes, and if it is successful, the time necesary to address this kind of problem will be significantly reduced... I think this is the right order to tackle.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Issues:
Resolves CryptoAlg-629
Description of changes:
This PR addresses the comments from @sebpop on the assembly functions developed to support ARMv8-optimized P-256 implementation.
Removed the prefetch instruction from select_w7 to
There was a noticeable small improvement in the performance of ECDSA sign (0.6%) and ECDH (0.2%) where multiplying by the base point is employed. It's more noticeable in ECDSA sign than ECDH since multiplication by the base point dominates ECDSA sign operation, but is only the first part of ECDH which also contains multiplication by an arbitrary public point which is a slower operation.
These improvements are understandably negligible, but they only show that prefetch, which may improve performance in some cases such as tree traversal and on platforms where there isn't a good hardware-supported prefetch, in this case, affects the performance (slightly) negatively.
Addressed other comments on the development application such as removing the
.archdirective and the-marchcompilation option.Enabled P-256 optimizations by default on ARMv8
which means reverting "CryptoAlg-530: Add ci test with -DOPENSSL_AARCH64_P256=1"
commit 270f803
Call-outs:
N/A
Testing:
Tested on ARMv8 EC2 instance.
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.