On Fri, Nov 13, 2015 at 09:22:52AM -0700, Jens Axboe wrote: > On 11/13/2015 09:13 AM, Mike Galbraith wrote: > >On Fri, 2015-11-13 at 08:36 -0700, Jens Axboe wrote: > >>Previous patch was obvious pre-coffee crap, this should work for using > >>ktime to spin max 1usec. > > > >1us seems a tad low. I doubt the little wooden gears and pulleys of my > >core2 Toshiba Satellite lappy can get one loop ground out in a usec :) > > Maybe it is, it's based off the original intent of the function, > though. See the original commit referenced. I've been looking at numbers from one laptop and I can set the timeout at 2us before we see a steep decline in what is more or less synchronous request handling (which affects a variety of rendering workloads). Looking around, other busy loops seem to use local_clock() (i.e. rdstcll with a fair wind). Is that worth using here? -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
