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

[Keith Richie]

On Fri, May 1, 2009 at 1:26 AM, Keith Richie <disturbed1976 at gmail.com> wrote:
> On Fri, May 1, 2009 at 12:53 AM, Dave Johansen <davejohansen at gmail.com> wrote:
>> On Thu, Apr 30, 2009 at 5:35 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.
>>
>> iostat -x shows >85% idle, and iotop showed ~2.3 M/s read, but I still
>> see the stuttering.
>>
>> I'm still waiting to see the results of the long S.M.A.R.T. test, but
>> does anyone have any ideas on what the issue might be?
>>
>> Dave
>> _______________________________________________
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>>
>
> iostat -x shows >85% idle doesn't mean much here ;)
>
> Look at the %uti - the last column for your storage drive (md0/1/2 or
> sda/b/c ----)
>

Just to post some more info for you.

You are trying to found out why your system is Input/Output Bound.

Run mythbackend as normal. Start watching a show on the frontend as
normal - when the skipping starts - run iostat -x on the backend to
check util %.

I guess I should have spelled it out in the first post.