On 02/28/2013 05:18 PM, Mike Galbraith wrote: > On Thu, 2013-02-28 at 16:49 +0800, Michael Wang wrote: >> On 02/28/2013 04:24 PM, Mike Galbraith wrote: >>> On Thu, 2013-02-28 at 16:14 +0800, Michael Wang wrote: >>>> On 02/28/2013 04:04 PM, Mike Galbraith wrote: >>> >>>>> It would be nice if it _were_ a promise, but it is not, it's a hint. >>>> >>>> Bad to know :( >>>> >>>> Should we fix it or this is by designed? The comments after WF_SYNC >>>> cheated me... >>> >>> You can't fix it, because it's not busted. You can say "Ok guys, I'm >>> off for a nap RSN" all you want, but that won't guarantee that nobody >>> pokes you, and hands you something more useful to do than snoozing. >> >> So sync still means current is going to sleep, what you concerned is >> this promise will be easily broken by other waker, correct? > > That makes it a lie, and it can already have been one with no help. > Just because you wake one sync does not mean you're not going to find > another to wake. Smart tasks are taught to look before they leap. > >> Hmm.. may be you are right, if 'perf bench sched pipe' is not the one we >> should care, I have no reason to add this logical currently. > > Well, there is reason to identify task relationships methinks, you just > can't rely on the fact that you're alone on the rq at the moment, and > doing a sync wakeup to bind tasks. They _will_ lie to you :)
I see. > >> I will remove this plus branch, unless I found other benchmark could >> benefit a lot from it. >> >> Besides this, how do you think about this idea? > > I like the idea of filtering true buddy pairs, and automagically > detecting the point when 1:N wants spreading rather a lot (fwtw). I'll > look closer at your method, but when it comes to implementation > opinions, the only one I trust comes out of a box in front of me. And please let me know how it works on your box ;-) Regards, Michael Wang > > I'm somewhat.. "taste challenged", Peter and Ingo have some though :) > > -Mike > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/