Hector Centeno wrote: > Thanks for your responses, > > I was comparing same latency settings, but it's true, it's unfair to > compare a two channel interface with a 10+midi one. Nevertheless the CPU usage of freebob/ffado is higher than that of usb devices. > > Pieter: I'm using jack and freebob from the Ubuntu repositories > (libfreebob0 version 1.0.7-1). Is that a debug build? Probably not. Greets, Pieter > > Regards, > > Hector > > > On Sun, Sep 21, 2008 at 5:24 AM, Pieter Palmers <pieterp@xxxxxxx> wrote: >> hollunder@xxxxxx wrote: >>> On Sun, 21 Sep 2008 01:06:21 -0400 >>> "Hector Centeno" <hcengar@xxxxxxxxx> wrote: >>> >>>> Hello, >>>> >>>> I have two computers (desktop and laptop) with Ubuntu Hardy (using >>>> kernel RT on both) and a Edirol FA-101 firewire interface. I was >>>> comparing Jack's CPU usage (no other audio app running) using the >>>> Edirol against a USB M-Audio Transit. I noticed on both computer the >>>> CPU usage to be much higher with the firewire interface than with the >>>> USB. On my laptop goes up to 15% or more and 8% on my desktop >>>> (Centrino Duo @ 1.7GHz and Core 2 Duo @ 2.1 GHz respectively) while >>>> using the USB interface the usage remains below 1%. Is this a normal >>>> behaviour of firewire interfaces? Is this a Jack related issue? Is >>>> there a recent and more efficient version of Freebob (ffado maybe?) >>>> than the one from the Ubuntu repos? >>>> >>>> Cheers, >>>> >>>> Hector >>> Are you sure that you are comparing the same latency settings? Just >>> a thought because Firewire is capable of lower latencies than USB and >>> lower latencies also mean higher cpu usage. >>> As said, just a thought, I never used FW. >> This is partially true. >> >> The fact that the transit has only a channel count of 2in/4out while the >> FA-101 has 10in/10out + midi makes that it's not really a fair comparison. >> >> However the main issue is that the kernel-space firewire implementation >> is not very CPU efficient. There are some issues with how DMA memory >> coherence is implemented that make things CPU intensive. Messing with >> the kernel level implementation to improve CPU consumption is not >> considered a priority for the freebob/ffado developers ATM. The 'new' >> firewire kernel drivers will allow us to implement a more efficient >> scheme reducing CPU. But let's first get the current FFADO out. >> >> FreeBoB/FFADO themselves are fairly CPU efficient, although things can >> always be improved. >> >> Greets, >> >> Pieter >> >> PS: you don't by any chance use a freebob/ffado debug build? >> _______________________________________________ >> Linux-audio-user mailing list >> Linux-audio-user@xxxxxxxxxxxxxxxxxxxx >> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user >> > _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
