Return agent response length.#1170
Merged
Merged
Conversation
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #1170 +/- ##
==========================================
+ Coverage 71.42% 71.44% +0.02%
==========================================
Files 348 348
Lines 54522 54719 +197
==========================================
+ Hits 38942 39096 +154
- Misses 15580 15623 +43
🚀 New features to boost your workflow:
|
VianneyRuhlmann
approved these changes
Aug 4, 2025
| #[no_mangle] | ||
| pub unsafe extern "C" fn ddog_trace_exporter_response_get_body( | ||
| response: *const ExporterResponse, | ||
| out_len: Option<&mut usize>, |
Contributor
There was a problem hiding this comment.
Would it be simpler if we turned ExporterResponse to Repr(C) and access fields directly ?
Contributor
Author
There was a problem hiding this comment.
I thought about that but changing the ExporterResponse in any way will result in an ABI incompatibility, for example returning the headers or parsing headers info. Probably it won't matter too much because tracers always recompile the bindings with each new version but I think it's a good practice to return opaque pointers for types that are subject to change.
Contributor
There was a problem hiding this comment.
Ok, on compatibility note you could add a new getter to retrieve len instead of modifying the existing signature. Although since dotnet is the only tracer using the bindings for now both are fine.
Contributor
Author
There was a problem hiding this comment.
Indeed at first I thought about just adding a new getter but since .Net was the only one using the API I decided to change it in order to reduce the performance overhead of crossing the managed side boundary two times for each agent response.
…rned into a null terminated string.
BenchmarksComparisonBenchmark execution time: 2025-08-06 09:58:38 Comparing candidate commit 4066a4a in PR branch Found 2 performance improvements and 0 performance regressions! Performance is the same for 51 metrics, 2 unstable metrics. scenario:credit_card/is_card_number/378282246310005
CandidateCandidate benchmark detailsGroup 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Group 8
Group 9
Group 10
Group 11
Group 12
Group 13
Group 14
BaselineOmitted due to size. |
VianneyRuhlmann
approved these changes
Aug 6, 2025
Contributor
Author
|
/merge |
|
View all feedbacks in Devflow UI.
The expected merge time in
|
dd-devflow
Bot
added
mergequeue-status: queued
mergequeue-status: in_progress
and removed
mergequeue-status: queued
labels
This was referenced Aug 6, 2025
Merged
andrewlock
pushed a commit
to DataDog/dd-trace-dotnet
that referenced
this pull request
Aug 8, 2025
## Summary of changes - Bump version from 19.1.0 to 20.0.0. - Update GetResponseBody signature. ## Reason for change API Changes: - `ddog_trace_exporter_response_get_body` now returns the length which prevents managed code to compute the payload's length manually. Improvements: - Avoid formatting the agent response into a null terminated string before returning it to the managed code. This will boost the performance by avoiding an additional copy of the response ([#1170](DataDog/libdatadog#1170)). - Lower the severity of the info fetcher logs [#1168](DataDog/libdatadog#1168). ## Other details Libdd release [page](https://github.com/DataDog/libdatadog/releases/tag/v20.0.0)
This file contains hidden or 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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
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.
What does this PR do?
The calling code will need to deserialize the response in order to get the sample rates for that it will need the length of the response which can be computed by iterating over the response looking for the NUL character. This results in extra computation in the calling code and this PR address this situation. Moreover the FFI layer was making an additional copy of the payload to turn it into a CString, this was also removed.
Motivation
Avoid performance penalties while deserializing the response.