Merge pull request #8522 from lizan/write_compressed_byte_buffer

Skip compress filter if byte_buffer is compressed

src/core/lib/channel/compress_filter.c

@@ -111,9 +111,13 @@ static grpc_mdelem *compression_md_filter(void *user_data, grpc_mdelem *md) {
   return md;
 }
 
-static int skip_compression(grpc_call_element *elem) {
+static int skip_compression(grpc_call_element *elem, uint32_t flags) {
   call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
+
+  if (flags & (GRPC_WRITE_NO_COMPRESS | GRPC_WRITE_INTERNAL_COMPRESS)) {
+    return 1;
+  }
   if (calld->has_compression_algorithm) {
     if (calld->compression_algorithm == GRPC_COMPRESS_NONE) {
       return 1;
@@ -241,8 +245,8 @@ static void compress_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
   if (op->send_initial_metadata) {
     process_send_initial_metadata(elem, op->send_initial_metadata);
   }
-  if (op->send_message != NULL && !skip_compression(elem) &&
-      0 == (op->send_message->flags & GRPC_WRITE_NO_COMPRESS)) {
+  if (op->send_message != NULL &&
+      !skip_compression(elem, op->send_message->flags)) {
     calld->send_op = op;
     calld->send_length = op->send_message->length;
     calld->send_flags = op->send_message->flags;

src/core/lib/surface/call.c

@@ -1461,6 +1461,12 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         grpc_slice_buffer_stream_init(
             &call->sending_stream,
             &op->data.send_message->data.raw.slice_buffer, op->flags);
+        /* If the outgoing buffer is already compressed, mark it as so in the
+           flags. These will be picked up by the compression filter and further
+           (wasteful) attempts at compression skipped. */
+        if (op->data.send_message->data.raw.compression > GRPC_COMPRESS_NONE) {
+          call->sending_stream.base.flags |= GRPC_WRITE_INTERNAL_COMPRESS;
+        }
         stream_op->send_message = &call->sending_stream.base;
         break;
       case GRPC_OP_SEND_CLOSE_FROM_CLIENT: