> > > Eh ??? > > > if (foo) bar(); else baz(); > > > will probably execute faster than: > > > (*bar_baz)(); > > > since the indirect jump is (IIRC) always unpredicted. > > > > What do you have to predict on unconditional branches? > > The branch destination. E.g. the CPU can't start prefetching from the > bar().
Probably you guys should check diffs first: + if (sc->write_mbuf == NULL) + sc->write_mbuf = dp8390_write_mbuf; : - if (sc->write_mbuf) - len = (*sc->write_mbuf)(sc, m0, buffer); - else - len = dp8390_write_mbuf(sc, m0, buffer); + len = (*sc->write_mbuf)(sc, m0, buffer); i.e. + if (!foo) foo = bar; : - if (foo) (*foo)() else inlined_bar() + (*foo)() Few (no?) drivers use the latter inlined one so no befefit of prefetch with predict. --- Izumi Tsutsui
