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

Dave Johansen davejohansen at gmail.com
Sat May 2 14:12:27 UTC 2009


On Thu, Apr 30, 2009 at 10:28 PM, Keith Richie <disturbed1976 at gmail.com> wrote:
> 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._______________________________________________
>>>>> mythtv-users mailing list
>>>>> mythtv-users at mythtv.org
>>>>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>>>>
>>>>
>>>> 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
>>> _______________________________________________
>>> mythtv-users mailing list
>>> mythtv-users at mythtv.org
>>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>>
>>
>> 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.

So I just tried watching a recording of SNL while not recording
anything and the util% bounces around 98% and will occasionally hit
100%.

But I've record 2 shows before while watching something so I wondered
how that works. I then set it to record a show and the util% was
basically 0% with occasional spike to 1 or 2%.

If I changed to Watch TV and watched that show, then the util% bounced
between 10 and 35% but was usually in the 15-20% range.

So then I tried watching that same episode of SNL while the recording
was happening and the util% hung out at around 5-10%.

So what does this mean?

Thanks,
Dave


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