On Thu, Dec 15, 2016 at 11:08:49AM +0200, Jani Nikula wrote: > On Thu, 15 Dec 2016, Nicholas Mc Guire <hofrat@xxxxxxxxx> wrote: > > Even on fast systems a 2 microsecond delay is most likely more efficient > > as a busy-wait loop. The overhead of a hrtimer does not seem warranted - > > change this to a udelay(2). > > Similar concerns as in [1]. We don't need the accuracy of udelay() here, > so this boils down to which is the better use of CPU. We could probably > relax the max delay more if that was helpful. But I'm not immediately > sold on "is most likely more efficient" which sounds like a gut feeling. > > I'm sorry it's not clear in my other reply that I do appreciate > addressing incorrect/silly use of usleep_range(); I'm just not (yet) > convinced udelay() is the answer. if the delay is not critical and all that is needed is an assurance that it is greater than X us then usleep_range is fine with a relaxed limit. So from what you wrote my patch proposal is wrong - the udelay() is not the way to got. My intent is to get rid of very small usleep_range() cases so if usleep_range(20,50) causes no issues with this driver and does not induce any performance penalty then that would be the way to go I think. thx! hofrat _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
