increased cache line size for high performance seeds

src/session.cpp

@@ -197,6 +197,8 @@ namespace libtorrent
 		set.cache_size = 32768;
 		set.use_read_cache = true;
 		set.cache_buffer_chunk_size = 128;
+		settings.read_cache_line_size = 512;
+		settings.write_cache_line_size = 512;
 		// one hour expiration
 		set.cache_expiry = 60 * 60;