Re: ehci-hcd affects hda speed

["Alessandro Suardi" <alessandro.suardi@gmail.com>]

On Wed, Mar 5, 2008 at 5:19 PM, Rene Herman <rene.herman@keyaccess.nl> wrote:
> On 04-03-08 23:27, Lev A. Melnikovsky wrote:
>
>  > I have recently installed a VT6212L-based PCI USB controller into my old
>  > rock-stable P3B-F computer
>
>  Uh oh...
>
>  > just to discover that, even being idle, it significantly slows down main
>  > PATA hard drive. I have found an earlier thread with similar (?) problem
>  > (archived at http://marc.info/?t=111749614000002&r=1&w=2 ) but it
>  > provides no solution. Can this behaviour be explained? Can it be fixed?
>
>  Yes, that one was my same problem. It was diagnosed to the VT6212L doing
>  decidedly weird things with toggling the Async bit and tying up the bus.
>  People seemed reluctant to either confirm or deny my suspicion that this was
>  VIA trying to shine on benchmarks while screwing you over so what exactly
>  that amounts to I don't know. My own solution has consisted of replacing the
>  controller with a somewhat slower but decent NEC controller and selling of
>  the VIA crapware to some unsuspecting poor sod...
>
>  > There's one thing that makes me optimistic: USB traffic _speeds_up_ hda.
>  > That is hdparm gives ~20% improvement in buffered reads if a USB flash
>  > is inserted and another xterm simultaneously runs
>  > # dd if=/dev/sda of=/dev/null bs=1024
>
>  Sort of interesting. I doubt something can be done about the idle thing
>  though but David is the person to talk to. Leaving in the rest:
>
>  > Here's what I see:
>  >
>  > ------------------------------------------------------------------------------
>  >
>  > # hdparm -t -T /dev/hda
>  >     /dev/hda:
>  >      Timing cached reads:   312 MB in  2.01 seconds = 155.60 MB/sec
>  >      Timing buffered disk reads:   88 MB in  3.06 seconds =  28.77 MB/sec
>  > # modprobe ehci-hcd
>  > # hdparm -t -T /dev/hda
>  >     /dev/hda:
>  >      Timing cached reads:   274 MB in  2.01 seconds = 136.58 MB/sec
>  >      Timing buffered disk reads:   44 MB in  3.10 seconds =  14.20 MB/sec
>  > # rmmod ehci-hcd
>  > # hdparm -t -T /dev/hda
>  >     /dev/hda:
>  >      Timing cached reads:   286 MB in  2.01 seconds = 142.48 MB/sec
>  >      Timing buffered disk reads:   90 MB in  3.06 seconds =  29.44 MB/sec
>  > ------------------------------------------------------------------------------
>  >
>  >
>  > And here's what I have (kernel 2.6.24.3):
>  >
>  > ------------------------------------------------------------------------------
>  >
>  > #lspci -v
>  >
>  > 00:09.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1
>  > Controller (rev 62) (prog-if 00 [UHCI])
>  >         Subsystem: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller
>  >         Flags: medium devsel, IRQ 5
>  >         I/O ports at d000 [size=32]
>  >         Capabilities: [80] Power Management version 2
>  >
>  > 00:09.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1
>  > Controller (rev 62) (prog-if 00 [UHCI])
>  >         Subsystem: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller
>  >         Flags: medium devsel, IRQ 9
>  >         I/O ports at b800 [size=32]
>  >         Capabilities: [80] Power Management version 2
>  >
>  > 00:09.2 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 65) (prog-if
>  > 20 [EHCI])
>  >         Subsystem: VIA Technologies, Inc. USB 2.0
>  >         Flags: bus master, medium devsel, latency 32, IRQ 11
>  >         Memory at d3800000 (32-bit, non-prefetchable) [size=256]
>  >         Capabilities: [80] Power Management version 2
>  >
>  > # cat /proc/interrupts
>  >            CPU0
>  >   0:  100814528    XT-PIC-XT        timer
>  >   1:       4057    XT-PIC-XT        i8042
>  >   2:          0    XT-PIC-XT        cascade
>  >   3:       1013    XT-PIC-XT
>  >   4:          2    XT-PIC-XT
>  >   5:    7165568    XT-PIC-XT        bttv0, FM801, uhci_hcd:usb2,
>  > uhci_hcd:usb3
>  >   8:   25956003    XT-PIC-XT
>  >   9:     661413    XT-PIC-XT        eth1, uhci_hcd:usb4
>  >  10:          4    XT-PIC-XT
>  >  11:   13526145    XT-PIC-XT        eth0, ehci_hcd:usb1
>  >  12:    1068179    XT-PIC-XT        i8042
>  >  14:     710123    XT-PIC-XT        ide0
>  >  15:       4365    XT-PIC-XT        ide1
>  > NMI:          0   Non-maskable interrupts
>  > TRM:          0   Thermal event interrupts
>  > SPU:          0   Spurious interrupts
>  > ERR:          0
>  > ------------------------------------------------------------------------------
>  >
>  >
>  > Please let me know if I missed something important.
>
>  Rene.
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>

I reported this problem well over an year ago, and it was never fixed.

http://lkml.org/lkml/2006/10/29/81

That old K7-800 is still serving as my bittorrent 24x7 box, now
 under the last FC6 kernel released. I plan to upgrade it to
 Fedora 9 once it's out, and it would be great if a fix to this bug
 could be found...

--alessandro

 "We act as though comfort and luxury were the chief requirements
   of life, when all that we need to make us really happy is
   something to be enthusiastic about."

   (Charles Kingsley)