diff --git a/.gitlab/container_build/docker_linux.yml b/.gitlab/container_build/docker_linux.yml
index 9dfd539b4676a..19289b03e5261 100644
--- a/.gitlab/container_build/docker_linux.yml
+++ b/.gitlab/container_build/docker_linux.yml
@@ -119,23 +119,6 @@ docker_build_agent7:
     TAG_SUFFIX: -7
     BUILD_ARG: --target test --build-arg PYTHON_VERSION=3 --build-arg DD_AGENT_ARTIFACT=datadog-agent_7*_amd64.deb
 
-single_machine_performance-push-main-sha:
-  stage: container_build
-  rules:
-    - !reference [.on_main_a7]
-  image: 486234852809.dkr.ecr.us-east-1.amazonaws.com/ci/datadog-agent-buildimages/docker_x64$DATADOG_AGENT_BUILDIMAGES_SUFFIX:$DATADOG_AGENT_BUILDIMAGES
-  tags: ["runner:docker"]
-  needs:
-    - docker_build_agent7
-  script:
-    - echo -n ${CI_COMMIT_SHA} > .main_sha
-    - SMP_ACCOUNT_ID=$(aws ssm get-parameter --region us-east-1 --name ci.datadog-agent.single-machine-performance-account-id --with-decryption --query "Parameter.Value" --out text)
-    - SMP_AGENT_TEAM_ID=$(aws ssm get-parameter --region us-east-1 --name ci.datadog-agent.single-machine-performance-agent-team-id --with-decryption --query "Parameter.Value" --out text)
-    - aws configure set aws_access_key_id $(aws ssm get-parameter --region us-east-1 --name ci.datadog-agent.single-machine-performance-bot-access-key-id --with-decryption --query "Parameter.Value" --out text) --profile single-machine-performance
-    - aws configure set aws_secret_access_key $(aws ssm get-parameter --region us-east-1 --name ci.datadog-agent.single-machine-performance-bot-access-key --with-decryption --query "Parameter.Value" --out text) --profile single-machine-performance
-    - aws configure set region us-west-2 --profile single-machine-performance
-    - aws s3 cp --profile single-machine-performance --only-show-errors .main_sha s3://${SMP_AGENT_TEAM_ID}-smp-artifacts/information/latest_main_sha
-
 single_machine_performance-amd64-a7:
   extends: .docker_publish_job_definition
   stage: container_build
diff --git a/.gitlab/functional_test/regression_detector.yml b/.gitlab/functional_test/regression_detector.yml
index 041f06ad69615..0d362fa22ef32 100644
--- a/.gitlab/functional_test/regression_detector.yml
+++ b/.gitlab/functional_test/regression_detector.yml
@@ -8,7 +8,10 @@ single-machine-performance-regression_detector:
   artifacts:
     expire_in: 1 weeks
     paths:
-      - submission_metadata
+      - submission_metadata              # for provenance, debugging
+      - ${CI_COMMIT_SHA}-baseline_sha    # for provenance, debugging
+      - outputs/report.md                # for debugging, also on S3
+      - outputs/report.html              # for debugging, also on S3
     when: always
   variables:
     SMP_VERSION: 0.7.3
@@ -22,7 +25,7 @@ single-machine-performance-regression_detector:
   # 'comparison'. We are guaranteed by the structure of the pipeline that
   # 'comparison' exists, not so much with 'baseline' as it has to come from main
   # merge pipeline run. This is solved in datadog-agent by updating a file in S3
-  # with the SHA of the latest passing build from main. It's solved in Vector by
+  # with the SHA of the merge base from main. It's solved in Vector by
   # building Vector twice for each Regression Detector run.
   #
   # We allow failure for now. _Unfortunately_ this also means that if the
@@ -30,6 +33,14 @@ single-machine-performance-regression_detector:
   # flagged.
   allow_failure: true
   script:
+    # Ensure output files exist for artifact downloads step
+    - mkdir outputs              # Also needed for smp job sync step
+    - touch outputs/report.md    # Will be emitted by smp job sync
+    - touch outputs/report.html  # Will be emitted by smp job sync
+    # Compute merge base of current commit and `main`
+    - git fetch origin
+    - SMP_MERGE_BASE=$(git merge-base ${CI_COMMIT_SHA} origin/main)
+    - echo "Merge base is ${SMP_MERGE_BASE}"
     # Setup AWS credentials for single-machine-performance AWS account
     - AWS_NAMED_PROFILE="single-machine-performance"
     - SMP_ACCOUNT_ID=$(aws ssm get-parameter --region us-east-1 --name ci.datadog-agent.single-machine-performance-account-id --with-decryption --query "Parameter.Value" --out text)
@@ -41,11 +52,15 @@ single-machine-performance-regression_detector:
     # Download smp binary and prepare it for use
     - aws --profile single-machine-performance s3 cp s3://smp-cli-releases/v${SMP_VERSION}/x86_64-unknown-linux-musl/smp smp
     - chmod +x smp
-    # Submit job, using the SHA of the last successful main commit as baseline.
-    # This will have been built in a separate pipeline run. The comparison will
-    # have been built previously in this pipeline run.
-    - aws --profile ${AWS_NAMED_PROFILE} s3 cp --only-show-errors s3://${SMP_AGENT_TEAM_ID}-smp-artifacts/information/latest_main_sha .latest_main_sha
-    - BASELINE_SHA=$(cat .latest_main_sha)
+    - BASELINE_SHA="${SMP_MERGE_BASE}"
+    - echo "Computing baseline..."
+    - echo "Checking if image exists for commit ${BASELINE_SHA}..."
+    - while [[ ! $(aws ecr describe-images --profile single-machine-performance --registry-id "${SMP_ACCOUNT_ID}" --repository-name "${SMP_AGENT_TEAM_ID}-agent" --image-ids imageTag="${BASELINE_SHA}-7-amd64") ]]; do echo "No image exists for ${BASELINE_SHA} - checking predecessor of ${BASELINE_SHA} next"; BASELINE_SHA=$(git rev-parse ${BASELINE_SHA}^); echo "Checking if image exists for commit ${BASELINE_SHA}..."; done
+    - echo "Image exists for commit ${BASELINE_SHA}"
+    - echo "Baseline SHA is ${BASELINE_SHA}"
+    - echo -n "${BASELINE_SHA}" > "${CI_COMMIT_SHA}-baseline_sha"
+    # Copy the baseline SHA to SMP for debugging purposes later
+    - aws s3 cp --profile single-machine-performance --only-show-errors "${CI_COMMIT_SHA}-baseline_sha" "s3://${SMP_AGENT_TEAM_ID}-smp-artifacts/information/"
     - BASELINE_IMAGE=${SMP_ECR_URL}/${SMP_AGENT_TEAM_ID}-agent:${BASELINE_SHA}-7-amd64
     - echo "${BASELINE_SHA} | ${BASELINE_IMAGE}"
     - COMPARISON_IMAGE=${SMP_ECR_URL}/${SMP_AGENT_TEAM_ID}-agent:${CI_COMMIT_SHA}-7-amd64
@@ -76,7 +91,6 @@ single-machine-performance-regression_detector:
             --wait-delay-seconds 60
             --submission-metadata submission_metadata
     # Now that the job is completed pull the analysis report, output it to stdout.
-    - mkdir outputs
     - RUST_LOG="${RUST_LOG}" ./smp --team-id ${SMP_AGENT_TEAM_ID} --aws-named-profile ${AWS_NAMED_PROFILE}
             job sync
             --submission-metadata submission_metadata
@@ -93,7 +107,7 @@ single-machine-performance-regression_detector:
     - dpkg -i dd-package.deb
     - rm dd-package.deb
     - apt-get update
-    - dd-package --bucket binaries.ddbuild.io --package devtools/dd-package-dev
+    - dd-package --bucket binaries.ddbuild.io --package devtools/dd-package-dev --distribution "20.04"
     # Kludge from https://gitlab.com/gitlab-org/gitlab-runner/-/issues/4645#note_287636439 to avoid
     # doubled output
     - echo ""
@@ -103,7 +117,8 @@ single-machine-performance-regression_detector:
     - "# beneath the error message in the GitLab CI logs                               #"
     - "#################################################################################"
     - echo ""
-    - dd-package --bucket binaries.ddbuild.io --package devtools/pr-commenter
+    # Pinned version of pr-commenter taken from https://github.com/DataDog/dogweb/blob/b2a891c2a2186b8fecd27ca9b13ebabe5f289a4a/tasks/gitlab/k8s-diff-helper.sh#L22
+    - dd-package --bucket binaries.ddbuild.io --package devtools/pr-commenter --distribution "20.04" --version "14692290-a6440fd1"
     # Post HTML report to GitHub
     - cat outputs/report.html | /usr/local/bin/pr-commenter --for-pr="$CI_COMMIT_REF_NAME"
     # Finally, exit 1 if the job signals a regression else 0.