2016-03-09 15:23, Ananyev, Konstantin: > > > > 2016-03-09 13:36, Ananyev, Konstantin: > > > > > + if (to_send == 0) > > > > > + return 0; > > > > > > > > Why this check is done in the lib? > > > > What is the performance gain if we are idle? > > > > It can be done outside if needed. > > > > > > Yes, that could be done outside, but if user has to do it anyway, > > > why not to put it inside? > > > I don't expect any performance gain/loss because of that - > > > just seems a bit more convenient to the user. > > > > It is handling an idle case so there is no gain obviously. > > But the condition branching is surely a loss. > > I suppose that condition should always be checked: > either in user code prior to function call or inside the > function call itself. > So don't expect any difference in performance here... > Do you have any particular example when you think it would? > Or are you talking about rte_eth_tx_buffer() calling > rte_eth_tx_buffer_flush() internally? > For that one - both are flush is 'static inline' , so I expect > compiler be smart enough to remove this redundant check. > > > So why the user would you like to do this check? > Just for user convenience - to save him doing that manually.
Probably I've missed something. If we remove this check, the function will do nothing, right? How is it changing the behaviour?
