While alpha testing 12.10, It seemed to me that the audio performance was much worse than with precise. (you may have seen some comments on IRC) Well, I rebooted to precise and it was now just as bad... what had changed? There was only one difference I could see. When testing ISO installs I install to a usb mass storage device (40 Gig). So I removed it and performance was like I remembered it, UBS audio IF with jack set to -p64 and wireless module unloaded was good for no xruns. clearly, the external hard drive was a problem but I needed it for testing. So maybe rtirq settings could help. The stock config is:
RTIRQ_NAME_LIST="rtc snd usb i8042" ps -eo comm,rtprio shows: irq/16-ehci_hcd 50 irq/16-uhci_hcd 80 irq/17-uhci_hcd 79 irq/18-uhci_hcd 78 irq/19-uhci_hcd 77 irq/12-i8042 74 irq/1-i8042 75 irq/8-rtc0 90 irq/16-ath9k 50 irq/45-eth0 50 irq/46-snd_hda_ 85 cat /proc/interrupts shows: 0: 8341859 0 IO-APIC-edge timer 1: 2462 0 IO-APIC-edge i8042 8: 1 0 IO-APIC-edge rtc0 9: 23283 0 IO-APIC-fasteoi acpi 12: 102653 0 IO-APIC-edge i8042 16: 2777 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb2, ath9k, i915 17: 0 0 IO-APIC-fasteoi uhci_hcd:usb3 18: 0 0 IO-APIC-fasteoi uhci_hcd:usb4 19: 0 0 IO-APIC-fasteoi uhci_hcd:usb5 44: 22184 0 PCI-MSI-edge ahci 45: 16167 0 PCI-MSI-edge eth0 46: 245 0 PCI-MSI-edge snd_hda_intel Hmm, well I have 3 USB ports... what are the rest for? Well, the others are used for other built in peripherals like web cam and SD reader. So I looked at dmesg to see what USB port my Audio IF was. USB2 as it turns out, so I reordered things to: rtc snd usb2 usb i8042 irq/16-ehci_hcd 80 irq/16-uhci_hcd 79 irq/17-uhci_hcd 74 irq/18-uhci_hcd 73 irq/19-uhci_hcd 72 irq/12-i8042 69 irq/1-i8042 70 irq/8-rtc0 90 irq/16-ath9k 78 irq/16-i915 77 irq/46-snd_hda_ 85 Hmm, ehci (USB1) is now 80, higher than USB2 (79). It seems that rtirq does priority by irq number. Looking at cat /proc/interrupts again I can see that 16: ehci_hcd:usb1, uhci_hcd:usb2, ath9k, i915 has lots of stuff on it. maybe USB2 is not so good to use... So I plugged the IF into each socket and was surprised to learn that the other two sockets were both usb3 (3:0 and 3:1). But at least USB3 is on it's own irq lets try that. Also, seeing as when I am using a USB IF I don't need internal sound I move that lower too: rtc usb3 snd i8042 usb irq/16-ehci_hcd 80 irq/16-uhci_hcd 70 irq/17-uhci_hcd 85 irq/18-uhci_hcd 68 irq/19-uhci_hcd 67 irq/12-i8042 74 irq/1-i8042 75 irq/8-rtc0 90 irq/16-ath9k 78 irq/16-i915 77 irq/46-snd_hda_ 80 Now my USB IF is higher than all the other USBs and the performance is back where it should be even when the usb drive is in USB2. I have to remember that the two usb ports on the right side of my computer are the same one. I have learned that it does matter what usb port I use. It is worth while finding out which port is which. So what are all the rest? USB1 = any port which has a USB 2.0 device. USB2 = left port USB3 = two right ports USB 4&5 ? I don't know, Maybe the standard USB chip comes with 5 ports and they only used 3. Webcam and SD use USB1. Len -- Len Ovens www.OvenWerks.net -- Ubuntu-Studio-devel mailing list [email protected] Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
