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

Dave Johansen davejohansen at gmail.com
Sat May 2 14:37:13 UTC 2009


On Sat, May 2, 2009 at 7:31 AM, Andrew Burgess <aab at cichlid.com> wrote:
> On Sat, 2009-05-02 at 07:12 -0700, Dave Johansen wrote:
>
>> > 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 %.
>> >
>> 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%.
>
> One thing that's different is the recording is happening to a different
> part of the disk each time.
>
> I had a WD disk recently that was really slow writing but only
> sometimes. It brought my entire raid array to a crawl. I noticed it by
> running atop (just a more visual way of running iostat). When I failed
> the disk and ran the array degraded everything was fine. I RMAed it and
> the replacement works fine. (this is the short version of the story, it
> took me a while to find the problem :-).
>
> I think the disk firmware just tried too long to recover bad sectors.
> Some drive manufacturers offer a special 'raid friendly' firmware
> version that fails quicker so the whole array doesn't stall.
>
> So for your case, can you use a spare/different disk just for recordings
> and see if that clears things up?
>
> HTH

Unfortunately, I just have a single hard drive and don't really have
access to another one to try anything like that.

Dave


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