On Thu, 10 Apr 2014 21:30:03 +0200 Christian König <deathsimple@xxxxxxxxxxx> wrote: > >>> Quick thought from someone entirely unfamiliar with the hardware: > >>> perhaps you can get the performance benefit without the size increase > >>> by moving the else portion into a non-inline function? I'm guessing > >>> that most accesses happen in the "if" branch. > >> The function call overhead is about equal to branching overhead, so > >> splitting it would only help about half that. It's called from many > >> places, and a lot of calls per sec. > > Actually direct register access shouldn't be necessary so often. Apart > from page flips, write/read pointer updates and irq processing there > shouldn't be so many of them. Could you clarify a bit more what issue > you are seeing here? Too much cpu usage for such a simple function. 2% makes it #2 in top-10 radeon.ko functions, right after evergreen_cs_parse. For reference, #3 (radeon_cs_packet_parse) is only 0.5%, one fourth of this function's usage. As proved by the perf increase, it's called often enough that getting rid of the function call overhead (and compiling the if out compile-time) helps measurably. - Lauri _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
