Mailing List archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[linux-dvb] Re: CPU Usage of kdvb-fe



Rene Bartsch wrote:
Am Die, 2003-06-10 um 15.23 schrieb Holger Waechtler:

Rene Bartsch wrote:

Shouldn't there be a fail-safe solution limiting CPU-load of kdvb-fe?

I don't think it is the right way to break a machine which may have
other important tasks because of bad weather ...
have you ever experienced something like this?


At my parents while hard rain and lightning the signal is sometimes lost
completely (90 cm dish directed and adjusted to ASTRA).

Just a few minutes ago two of three kdvb-fes on a server I'm maintaining
suddenly jumped up to 40 % each for some seconds. Usually they're
between 0.1 - 1%.
You don't need to report the time the kdvb-fe threads but the remaining idle time, this should always be >0.0%

If so the algorithm is working just fine, otherwise you maybe discovered a bug.


I also do not understand for what all this additional CPU-load is used.
the driver is trying to (re-?)aquiring the signal by zig-zag-scanning the frequency range around the center frequency. This is used to compensate temperature drift of LNBs and RF components used in the transmitters and receiver units.
Ok, but shouldn't be there some kind of limit? Think about four cards in
a machine starting zig-zag scanning because of some lightnings and the
machine acts like slow motion. Some limit in the driver like all
kdvb-processes together mustn't have more than 20% CPU-load would be
fine.
20% of what? of a machine running idle or one that's running 10x overloaded? Right now the code is written so that the threads should only eat cpu idle time. When no idle time is left then they'll zigzag much slower...

Holger



--
Info:
To unsubscribe send a mail to ecartis@linuxtv.org with "unsubscribe linux-dvb" as subject.



Home | Main Index | Thread Index