On Fri, 10 Jul 2009, Darren Hart wrote: > Subrata Modak wrote: > > On Fri, 2009-07-10 at 22:00 +0530, Sripathi Kodi wrote: > > > On Wednesday 08 July 2009 23:43:53 Subrata Modak wrote: > > > > Darren/Sri/Gowri, > > > > > > > > Where do you want me to put this exactly inside the RT tree ? > > > Hi Subrata, > > > > > > Going by how the tests are organized currently, I think this should go > > > into it's own directory under testcases/realtime/func. We will need to > > > add a makefile to it. Are you looking at us to help you with this? > > > > Correct. Please send me a patch which integrates it into RT tests build, > > install & run. > > Just got back from a week vacation and am burning through mail as fast as I > can :-) Haven't had a look yet, but does this test use librttest.h? I suspect > not. We'll need to adapt it to run within the existing ltp real-time testing > framework, which includes things like buffered output as well as mlocking > support. > > Lastly, I'm not sure this test does anything effectively different than > prio-wake, already in the tree. My other concerns with the test are its > explicit 1ms preemption criteria (as Steven described it anyway). We are > trying to move away from criteria being inherent in measurement tests, and 1 > ms seems like an awfully long priority inversion to be an acceptable criteria > to many users. > > Steven, am I missing something conceptually here? Hmm, I missed this email, sorry for the late reply. What does prio-wake do? This test is what I used to develop the rt scheduler in mainline (as well as in -rt). It wakes up N+1 tasks with lowering real time priorities. Where N is the number of CPUs in the system. Then it makes sure that the these tasks spread out across the CPUs. Most tests just test the highest priority task in the system. But those tests usually miss the second highest prio task in the system. If you have a second highest prio task in the system and a CPU is available to run, then it should run on that CPU. But what happens is that it can wait to be migrated and can take millisecs to wake up. This test makes sure that all the high prio tasks that are in the running state are actually running on a CPU if it can. Make sense? (BTW, current -rt and mainline now fail this test :-? ) -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
