On Thu, Aug 12, 2010 at 8:43 PM, Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > On Thu, Aug 12, 2010 at 02:11:22PM +0300, Felipe Contreras wrote: >> So far, nobody has refuted these: >> 1) opportunistic suspend needs a good behaved user-space to work properly > > As does dynamic power management. Thus remains unrefuted. >> 2) if suspend blockers are enabled in a system, *all* user-space must >> implement them to work correctly > > Really? From what I can see, only PM-driving applications need to use > suspend blockers. "PM-driving applications" is a new invention, so how do you know if an application belongs to this category or not? Some application might be non-PM-driving most of the time, but suddenly become PM-driving. Well, you have to analyze *all* of them. Think about this... is bash a PM driving application? No, but what if you run: 'sleep 3600 && alarm.sh'. Perhaps I should rewrite that as: 2) if suspend blockers are enabled in the system; *all* user-space is affected >> 3) implementing suspend blockers in user-space is not a straight-forward task > > Fortunately, experience thus far has shown that only a small fraction of > applications need to use suspend blockers. Wrong. We don't have any experience on that at all on typical linux ecosystems (remember that Android's user-space is very special). >> So, as the length of this thread has shown, the benefits of >> opportunistic suspend are *dubious* at best, and more likely not worth >> the changes needed in user-space which eventually will get pretty >> close to what suspend blockers can achieve even in ideal circumstances >> by just doing dynamic PM. > > The length of this thread (and the ones preceding it) is mostly due to > people talking past each other. Perhaps half of the thread, or even one quarter of the thread can be attributed to that, but still the rest I think it's because people keep pushing in, and people keep pushing out. > For example, the Android folks seem to > believe that it is important that relatively unskilled people be able > to write simple apps, and that the system nevertheless be able to run > these apps in a relatively energy efficient manner. Your proposals do > not address this issue. This might be because you are not aware of > this desire, because you are not aware of the computing history that > argues in favor of this requirement, or because you simply don't like > this requirement. Whatever the reason, until you face this requirement > head on, either addressing it or proving that it need not be addressed, > you will continue to be talking past the Android folks. This "requirement" is specific to Android's user-space, isn't it? Not Ubuntu, not Fedora, not MeeGo, not anyone with a typical user-space seems to be having this problem. I can argue to you that this problem can be solved in easier ways, but instead I will argue that perhaps we should wait for somebody besides Android to complain about it before providing a "solution". Because after all, what good is a "solution" provided by the kernel, if the user-space is not going to use it, ever. -- Felipe Contreras _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
