Docs: expand info about parallelism and concurrency control #4411

lib/utility.js

@@ -135,15 +135,9 @@ cache(true);
  * e.g. libaom manages its own 4 threads when encoding AVIF images,
  * and these are independent of the value set here.
  *
- * The maximum number of images that sharp can process in parallel
- * is controlled by libuv's `UV_THREADPOOL_SIZE` environment variable,
- * which defaults to 4.
- *
- * https://nodejs.org/api/cli.html#uv_threadpool_sizesize
- *
- * For example, by default, a machine with 8 CPU cores will process
- * 4 images in parallel and use up to 8 threads per image,
- * so there will be up to 32 concurrent threads.
+ * :::note
+ * Further {@link /performance|control over performance} is available.
+ * :::
  *
  * @example
  * const threads = sharp.concurrency(); // 4