net.server_epoll: Avoid concatenating buffer with single item

Saves creating a string that'll be identical to buffer[1] anyways, as
well as a C function call. Depending on Lua version and length of the
string, this could be reusing an interned string, but a longer one would
probably be duplicated for no reason.

Having exactly one item in the buffer seems like it would be fairly
common, but I have not done an extensive study. If opportunistic writes
are enabled then it will be even more likely.

This special case could be optimized like this in table.concat but it
does not look like it is.

1 files changed, 1 insertions, 1 deletions

diff --git a/net/server_epoll.lua b/net/server_epoll.lua
index e2c5f977..4ad142ce 100644
--- a/net/server_epoll.lua
+++ b/net/server_epoll.lua
@@ -408,7 +408,7 @@ function interface:onwritable()
 	self:onconnect();
 	if not self.conn then return; end -- could have been closed in onconnect
 	local buffer = self.writebuffer;
-	local data = t_concat(buffer);
+	local data = #buffer == 1 and buffer[1] or t_concat(buffer);
 	local ok, err, partial = self.conn:send(data);
 	if ok then
 		self:set(nil, false);