> > + num_element = > > + es58x_msg_num_element(es58x_dev->dev, > > + bulk_rx_loopback_msg->rx_loopback_msg, > > + msg_len); > > + if (unlikely(num_element <= 0)) > > + return num_element; > > Meta-comment on your use of 'unlikely' everywhere. Please drop it, it's > only to be used if you can actually measure the difference in a > benchmark. You are dealing with USB devices, which are really really > slow here. Also, humans make horrible guessers for this type of thing, > the compiler and CPU can get this right much more often than we can, and > we had the numbers for it (someone measured that 80-90% of our usages of > these markings are actually wrong on modern cpus). > > So just drop them all, it makes the code simpler to read and understand, > and the cpu can actually go faster. All those branch on which the unlikely() macro were applied were supposed to never been executed under normal circumstances. But I indeed have no benchmark to claim such use. Thank you for the detailed explanation, makes perfect sense. Each use of the likely()/unlikely() macros will be removed in v3 revision.
