Add zstd workaround to README. Add yaml formatting to code blocks. Move Cache segment restore to Known Practices section.

README.md

@@ -234,7 +234,7 @@ A cache gets downloaded in multiple segments of fixed sizes (`1GB` for a `32-bit
 
 #### Update a cache
 A cache today is immutable and cannot be updated. But some use cases require the cache to be saved even though there was a "hit" during restore. To do so, use a `key` which is unique for every run and use `restore-keys` to restore the nearest cache. For example:
-  ```
+  ```yaml
       - name: update cache on every commit
         uses: actions/cache@v3
         with:
@@ -248,6 +248,23 @@ A cache today is immutable and cannot be updated. But some use cases require the
 #### Use cache across feature branches
 Reusing cache across feature branches is not allowed today to provide cache [isolation](https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#restrictions-for-accessing-a-cache). However if both feature branches are from the default branch, a good way to achieve this is to ensure that the default branch has a cache. This cache will then be consumable by both feature branches.
 
+#### Improving cache restore performance on Windows
+Currently, cache restore is slow on Windows due to both tar being slow and the compression algorithm being used is `gzip`. Zstd was disabled on windows due to issues with bsd tar(libarchive) which is the tar implementation in use on Windows. To improve cache restore performance, we can re-enable `zstd` as the compression algorithm using the following workaround by using GNU tar instead.
+
+Add the following step to your workflow before the cache step:
+
+```yaml
+    - if: ${{ runner.os == 'Windows' }}
+      name: Use GNU tar
+      shell: cmd
+      run: |
+        echo "Adding GNU tar to PATH"
+        echo C:\Program Files\Git\usr\bin>>"%GITHUB_PATH%"
+```
+
+This should work on all Github Hosted runners as it is. For self-hosted runners, please ensure you have GNU tar and `zstd` installed.
+
+
 ## Contributing
 We would love for you to contribute to `actions/cache`, pull requests are welcome! Please see the [CONTRIBUTING.md](CONTRIBUTING.md) for more information.