[mythtv-users] VDPAU playback stuttering when XvMC playback is just fine?

[Richard Shaw]

On Thu, Apr 30, 2009 at 7:35 AM, Keith Richie <disturbed1976 at gmail.com> wrote:
> On Thu, Apr 30, 2009 at 1:38 AM, Jean-Yves Avenard <jyavenard at gmail.com> wrote:
>> Hi
>>
>>
>> On 30/04/2009, at 3:13 PM, Dave Johansen <davejohansen at gmail.com> wrote:
>>
>>> On Wed, Apr 29, 2009 at 10:09 PM, Jean-Yves Avenard <jyavenard at gmail.com>
>>> wrote:
>>>>
>>>> Hi
>>>>
>>>> On 30/04/2009, at 2:42 PM, Dave Johansen <davejohansen at gmail.com> wrote:
>>>>
>>>>>>
>>>>>
>>>>> I will give this a try and see if it helps with the stuttering.
>>>>>
>>>>>
>>>>
>>>> From your logs it's obvious you have issues with your machine not related
>>>> to
>>>> vdpau.
>>>>
>>>> Your PC seems to be IO bound for some reasons. Fix that first.
>>>>
>>>> I'm guessing the stream is corruted or interrupted
>>>
>>> How can I tell if my machine is IO bound?
>>> And if so how do I tell what the bottleneck is?
>>>
>>>
>>
>> Look at the log you posted earlier. There are tons of messages regarding  IO
>> bound issues, just google those
>>
>> There's not one single reason for those. Could be a kernel issue, could be
>> your hard drive (on the backend) is dodgy.
>>
>> Just google for those error
>> messages._______________________________________________
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>>
>
> IOBOUND errors are usually one of 2 things. Non optimal kernel
> configuration, or you've reached the limit of your system.
>
> Check to make sure you don't have any non essential services running
> in the background. Some distro's have those darned indexing utilities
> ;)
>
> Try changing the kernel scheduler, analyze your slab/slub performance
> (slabtop), and take a look at iostat.
>
> Running iostat -x will give you an output showing the utilization of
> your drives (last column). If it is at or near 100%, you've reached
> your limit.

I had the same symptom but may not be the same problem. I used top and
found I had a lot of IO waits then installed iotop and noticed that
the data transfer rates were WAY below what the drive should be
capable of. That's when I started suspecting the HD was going bad. A
short SMART test said the drive was good but when I did the long SMART
test it found lots of errors. Got a warranty replacement and all is
fine again.

Richard