write_stream_list(): Do not create threads to compress 1 chunk or less

diff --git a/src/write.c b/src/write.c
index a852c199670c9a6265cc043be19a6908d98c9ecb..63350bfc83bcaa8c61ca29a4bb6b688180c87f70 100644 (file)
--- a/src/write.c
+++ b/src/write.c
@@ -1430,11 +1430,11 @@ write_stream_list(struct list_head *stream_list,
         * to do compression.  There are serial and parallel implementations of
         * the chunk_compressor interface.  We default to parallel using the
         * specified number of threads, unless the upper bound on the number
-        * bytes needing to be compressed is less 2000000 (heuristic value).  */
+        * bytes needing to be compressed is less than a heuristic value.  */
        if (out_ctype != WIMLIB_COMPRESSION_TYPE_NONE) {
 
        #ifdef ENABLE_MULTITHREADED_COMPRESSION
-               if (ctx.num_bytes_to_compress >= 2000000) {
+               if (ctx.num_bytes_to_compress > max(2000000, out_chunk_size)) {
                        ret = new_parallel_chunk_compressor(out_ctype,
                                                            out_chunk_size,
                                                            num_threads, 0,