2.6.24-rc3-git3: usb hardware interrupts using 25% of CPU time

From: Frederik Himpe
Date: Wed Nov 28 2007 - 17:34:19 EST


I installed Linux 2.6.24-rc3-git3 on a PPC based Apple Powerbook G4
system. Now with top I see that over 20% of CPU time is used by hardware
interrupts. Looking at /proc/interrupts, the number in the row
ohci_hcd:usb1 is rising very quickly:

$ cat /proc/interrupts
CPU0
21: 1 MPIC 1 Edge i2sbus: i2s-a (tx)
24: 11008 MPIC 1 Level ide1
25: 33608 MPIC 1 Level VIA-PMU
26: 56 MPIC 1 Level keywest i2c
27: 1 MPIC 1 Edge i2sbus: i2s-a (rx)
29: 281578 MPIC 1 Level ohci_hcd:usb1
30: 0 MPIC 1 Level i2sbus: i2s-a (control)
31: 0 MPIC 1 Level i2sbus: i2s-b (control)
33: 1 MPIC 1 Edge i2sbus: i2s-b (tx)
34: 1 MPIC 1 Edge i2sbus: i2s-b (rx)
39: 41611 MPIC 1 Level ide0
40: 2 MPIC 1 Level ohci1394
41: 0 MPIC 1 Level eth0
42: 0 MPIC 1 Level keywest i2c
47: 2826 MPIC 1 Level GPIO1 ADB
48: 58633 MPIC 1 Level radeon@pci:0000:00:10.0
52: 18961 MPIC 1 Level b43
53: 1 MPIC 1 Level yenta
61: 1 MPIC 1 Edge headphone-detect
63: 0 MPIC 1 Level ohci_hcd:usb2, ohci_hcd:usb3,
ehci_hcd:usb4
BAD: 187917

$ lspci -nn
0000:00:0b.0 Host bridge [0600]: Apple Computer Inc. UniNorth 2 AGP
[106b:0034]
0000:00:10.0 VGA compatible controller [0300]: ATI Technologies Inc RV350
[Mobility Radeon 9600 M10] [1002:4e50]
0001:10:0b.0 Host bridge [0600]: Apple Computer Inc. UniNorth 2 PCI
[106b:0035]
0001:10:12.0 Network controller [0280]: Broadcom Corporation BCM4306
802.11b/g Wireless LAN Controller [14e4:4320] (rev 03)
0001:10:13.0 CardBus bridge [0607]: Texas Instruments PCI1510 PC card
Cardbus Controller [104c:ac56]
0001:10:17.0 Unknown class [ff00]: Apple Computer Inc. KeyLargo/Intrepid
Mac I/O [106b:003e]
0001:10:19.0 USB Controller [0c03]: Apple Computer Inc. KeyLargo/Intrepid
USB [106b:003f]
0001:10:1a.0 USB Controller [0c03]: Apple Computer Inc. KeyLargo/Intrepid
USB [106b:003f]
0001:10:1b.0 USB Controller [0c03]: NEC Corporation USB [1033:0035] (rev
43)
0001:10:1b.1 USB Controller [0c03]: NEC Corporation USB [1033:0035] (rev
43)
0001:10:1b.2 USB Controller [0c03]: NEC Corporation USB 2.0 [1033:00e0]
(rev 04)
0002:24:0b.0 Host bridge [0600]: Apple Computer Inc. UniNorth 2 Internal
PCI [106b:0036]
0002:24:0d.0 Unknown class [ff00]: Apple Computer Inc. UniNorth/Intrepid
ATA/100 [106b:003b]
0002:24:0e.0 FireWire (IEEE 1394) [0c00]: Apple Computer Inc. UniNorth 2
FireWire [106b:0031] (rev 81)
0002:24:0f.0 Ethernet controller [0200]: Apple Computer Inc. UniNorth 2
GMAC (Sun GEM) [106b:0032] (rev 80)


Full dmesg, .config and lsmod output can be found on
http://artipc10.vub.ac.be/linux-2.6.24-rc3-git3/

--
Frederik Himpe

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