qingstor: add upload chunk size/concurrency/cutoff control #2851

* --upload-chunk-size
* --upload-concurrency
* --upload-cutoff

docs/content/qingstor.md

@@ -234,4 +234,50 @@ Number of connection retries.
 - Type:        int
 - Default:     3
 
+#### --qingstor-upload-cutoff
+
+Cutoff for switching to chunked upload
+
+Any files larger than this will be uploaded in chunks of chunk_size.
+The minimum is 0 and the maximum is 5GB.
+
+- Config:      upload_cutoff
+- Env Var:     RCLONE_QINGSTOR_UPLOAD_CUTOFF
+- Type:        SizeSuffix
+- Default:     200M
+
+#### --qingstor-chunk-size
+
+Chunk size to use for uploading.
+
+When uploading files larger than upload_cutoff they will be uploaded
+as multipart uploads using this chunk size.
+
+Note that "--qingstor-upload-concurrency" chunks of this size are buffered
+in memory per transfer.
+
+If you are transferring large files over high speed links and you have
+enough memory, then increasing this will speed up the transfers.
+
+- Config:      chunk_size
+- Env Var:     RCLONE_QINGSTOR_CHUNK_SIZE
+- Type:        SizeSuffix
+- Default:     4M
+
+#### --qingstor-upload-concurrency
+
+Concurrency for multipart uploads.
+
+This is the number of chunks of the same file that are uploaded
+concurrently.
+
+If you are uploading small numbers of large file over high speed link
+and these uploads do not fully utilize your bandwidth, then increasing
+this may help to speed up the transfers.
+
+- Config:      upload_concurrency
+- Env Var:     RCLONE_QINGSTOR_UPLOAD_CONCURRENCY
+- Type:        int
+- Default:     4
+
 <!--- autogenerated options stop -->