On Wed, 2010-06-23 at 15:40 -0600, Gustin Johnson wrote:
On 10-06-22 09:42 AM, Ralf Mardorf wrote:
> Gustin Johnson wrote:
>> On 10-06-21 08:42 AM, Daniel James wrote:
>>
>>> Hi Ralf,
>>>
>>>
>>>>> FAIL
>>>>>
>>>> best latency was 1.29 ms
>>>> worst latency was 7.00 ms, which is too much.
>>>>
>>> Thanks for running those tests, that's very helpful.
>>>
>>> I'd be interested to know if other users can 'pass' this test using our
>>> current distros and kernels. If not, it seems like we have some more
>>> tweaking to do :-)
>>>
>>>
>> Those values are what you can expect with USB MIDI. If you have no
>> choice but to use USB gear then try to minimize the number of USB
>> devices that are in use. For example use PS/2 based HIDs (aka keyboard
>> and mouse). Disconnect any other USB devices (such as printers and
>> scanners).
>>
>> Even doing that I do not think that there is much room for improvement.
>>
>> In the next couple of days I will try and test my own rig with the RME
>> and USB MIDI interfaces.
>
> It's the only USB device in use. Mouse and keyboard are PS/2 devices, my
> printer isn't in use, but still a parallel port one and the USB stick is
> just for temporarily backups and usually not connected.
>
> I did start a reply regarding to rtirq defaults for USB and I started an
> experiment, but then my PATA hard disk failed and there is an issue with
> GRUB for my SATA.
>
The limitations are with how USB actually works. It was not designed
for low latency responsiveness. Messing with IRQs is going to be
enough. You might see some improvement, but not enough to make a
difference.
Yep
.
> I wasted my whole day with trying to repair GRUB for the SATA, but it
> didn't work.
> Then I tried to run a live cd, to get access to the internet, but there
> is no new live cd with PPPoE and a lot of old live cds didn't run on my
> computer or didn't support PPPoE too.
>
If GRUB was installed on the PATA, you will need to install it into your
SATA drive. The difficulty will scale with the number of hard drives
and OSs that you have installed. I know that your system can be
rescued. Most rescue distros have the option to boot an OS off of your
hard drive. The one I use and love is systemrescuecd, though it is very
much CLI orientated.
101% ACK regarding to the systemrescuecd, it's my favourite too
, but it failed. I guess there's something esoterically for Suse, because I could solve it using the Suse install DVD. While everything was ok for 64 Studio 2.1, after using an Ubuntu live cd, the same way I would have used a systemrescuecd (with one difference, for the Ubuntu CD I had PPPoE, but not for the systemrescuecd).
> Now I run the Ubuntu 7.10 live cd from a German magazine from 2008, it
> ships with pppoeconf.
>
> Fazit: At the moment I don't have access to the ALSA MIDI latency
> packages and I can't run 64 Studio 3.0 beta and 3.3 alpha, both are on
> the broken PATA.
>
> Tomorrow, perhaps tonight, I'll try to get access to my SATA, resp. to
> Suse 11.2. I don't have the time to do it now.
>
> Hopefully my PATA will start just one time again, to get it completely
> up-to-date backuped, at the moment it's disconnected to nurse it.
>
What exactly is wrong with it? If you cannot mount it from a live CD,
then the drive is probably toast.
The drive is absolutely 'toast' (I guess I translated 'toast' correctly
. 'Click-click'
...
Gene Heskett about how to handle a hard disk drive:
One could also use a hammer
with plastic faces in case the hand bruises easily. ;-)
Quoted out of context ... I'm laughing out loud. But you're right, I've got nothing to lose. Thank you.
The HD is 4 years old and I do a startup several times a day. Not good for the HDs, but the power bill vs the costs of a HD
. I wasn't surprised when it was broken and for any HD >= 2years I do backups very often
. Anyway, Gene's idea is very cool.
It will take around 7 days and I'm back to 64 Studio 3.0 and 3.3
... with a loss of 3 days regarding to the systems backups, but just 1 day regarding to a thunderbird backup.
And again, full ACK regarding to the systemrescuecd, it fix everything regarding to DEB Linuxes, but not to Suse, while Suse 64-bit has got advantages regarding to 32-bit apps. I guess for the future I'll prefer DEB @ 32-bit
, resp. 64 Studio 4.0 i369
.
Cheers!
Ralf
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ALSA MIDI latency test - was: opensource.com talk
