[libcxx-commits] [libcxx] [libc++] Add scripts to run benchmarks and submit to LNT on a regular basis (PR #180849)

[Louis Dionne via libcxx-commits]

ldionne wrote:

Tested with:

```
lnt create my-instance
cp libcxx/utils/ci/lnt/schema.yaml my-instance/schemas/libcxx.yaml
lnt runserver my-instance
```

```
# fake-submit.sh
source .venv/bin/activate

sha=${1}

echo "Starting to benchmark ${sha}..."

sleep 10

echo "Submitting data for $sha"
cat <<EOF > x.lnt
foo.execution_time 3
EOF
order=$(git rev-list $sha | wc -l)
lnt importreport --testsuite libcxx --order ${order} --run-info git_sha=$sha --machine my-machine x.lnt x.json
lnt submit http://localhost:8000/db_default/v4/libcxx/submitRun x.json
```

Then,

```
./libcxx/utils/ci/lnt/commit-watch -v --lnt-url http://localhost:8000 --test-suite libcxx --machine my-machine | while read commit; do ./fake-submit.sh $commit; done
```


https://github.com/llvm/llvm-project/pull/180849