Messages in this thread |  | | Date | Fri, 21 Sep 2001 18:18:00 +0200 | From | Stefan Westerfeld <> | Subject | Re: [PATCH] Preemption Latency Measurement Tool |
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Hi!
On Fri, Sep 21, 2001 at 02:42:56AM +0200, Roger Larsson wrote: > > You might try stracing artsd to see if it hangs at a particular syscall. > > Use -tt or -r for timestamps and pipe the output through tee (to a file on > > your ramfs). > > I tried playing a mp3 with noatun via artsd. Starting dbench 32 I get the > same kind of dropouts - and no indication with my latency profiling patch => > no process with higher prio is waiting to run! > > One of noatun or artsd is waiting for something else! (That is why I included > Stefan Westerfeld... artsd) > > I noticed very nice improvement then reniceing (all) artsd and noatun. > (I did also change the buffer size in artsd down to 40 ms) > > (This part most for Stefan... > So I thought - lets try to run artsd with RT prio - changed the option > HOW can it get RT prio when it is not suid? I guess it can not... > > So I manually added suid bit - but then noatun could not connect with > artsd... bug?, backed out the suid change... but is behaves as it works, > could be that it has so short bursts that prio never get a chance to drop)
If you want to run artsd with RT prio, add suid root to artswrapper if it is not already there - it should by default, but some distributors/packagers don't get this right. If you start artsd via kcminit, check the realtime checkbox, if you do manually, run artswrapper instead of artsd, i.e.
stefan@voyager:~/src/kdelibs/arts$ artswrapper -F10 -S4096 >> running as realtime process now (priority 50)
Artsd itself will not acquire RT prio, only artswrapper will. Noatun doesn't contain time critical code, so there it doesn't matter.
Cu... Stefan -- -* Stefan Westerfeld, stefan@space.twc.de (PGP!), Hamburg/Germany KDE Developer, project infos at http://space.twc.de/~stefan/kde *- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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