Attempted summary of suspend-blockers LKML thread, take two
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From: Pavel Machek on 9 Aug 2010 03:30 Hi! > >I should have asked this earlier... What exactly are the apps' > >compatibility constraints? Source-level APIs? Byte-code class-library > >invocations? C/C++ dynamic linking? C/C++ static linking (in other > >words, syscall)? > > For Java/Dalvik apps, the wakelock API is pertty high level -- it > talks to a service via RPC (Binder) that actually interacts with the > kernel. Changing the basic kernel<->userspace interface (within Strange. Arve claimed that open/close is too slow, and few microseconds faster ioctl is needed, and now we learn it actually uses RPC. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Brian Swetland on 9 Aug 2010 03:40
On Mon, Aug 9, 2010 at 12:26 AM, Pavel Machek <pavel(a)ucw.cz> wrote: > Hi! > >> >I should have asked this earlier... What exactly are the apps' >> >compatibility constraints? Source-level APIs? Byte-code class-library >> >invocations? C/C++ dynamic linking? C/C++ static linking (in other >> >words, syscall)? >> >> For Java/Dalvik apps, the wakelock API is pertty high level -- it >> talks to a service via RPC (Binder) that actually interacts with the >> kernel. Changing the basic kernel<->userspace interface (within > > Strange. Arve claimed that open/close is too slow, and few > microseconds faster ioctl is needed, and now we learn it actually uses > RPC. For the high level Java API, yes. For lower level userspace code, like the code that processes keypresses, the kernel interface is used directly. I think an open/close per keypress would be a bit excessive, for example. In any case, that ignores the fact that it's useful to have statistics, which are tricky to maintain meaningfully if you destroy the handle after use every time (by closing the fd). Brian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |