Hi.
Maybe I need to be more precise by saying that the DVB drivers seems to be the cause of this.
The load is generated due to a high rate of interrupts and context switches, when running with a configured DVB adapter. I'd like to ask if someone else experiences the same issues.
I'm running a x86_64 ubuntu natty with v4l-dvb-dkms from ppa:yavdr/main. The DVB adaters are one Hauppauge HVR4000 (cx88) and two Technisat Skystar HD2 (mantis/stb0899). The behavior is also present, when running with the cx88 based card only (knowing that mantis driver has issues with interrupts).
Without tvheadend accessing the adapters, the system has about 200 interrupts/sec and 200 context switches per sec. When starting with the card HVR4000, the interrupts increase to 450 interrupts/sec and the context switches get up to 800 context switches per sec.
"idle scanning", "signal monitoring" and "autodetect muxes" is turned of and no client is connected.