On Mon, 2009-07-20 at 10:03 -0700, Darren Hart wrote: > Steven Rostedt wrote: > > 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? > > Yup. This is different than prio-wake. Prio-wake creates some number > of threads of varying priorities and puts them to sleep on > pthread_cond_wait and then wakes them with pthread_cond_broadcast, then > tests that the threads were woken in priority order. Fails on > kernels/glibc without requeue pi support as a FUTEX_WAKE(all) was used > for PI mutexes. > > So to include this in the ltp/restcases/realtime suite, the test should > make use of the librttest.c and libstats.c apis, standardized argument > parsing, buffered logging mechanism, and standardized output formatting. > I can't get to that for a little while myself, but can assist if you > have any questions. Alternatively we can wait a little while, and > perhaps someone on my team will be able to help merge it with the > realtime test infrastructure in LTP. That should be fine. Regards-- Subrata > > > > > (BTW, current -rt and mainline now fail this test :-? ) > > Hrm, uh oh. Adding it to my lengthy list of things to try and look at :/ > > Thanks 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
