[mythtv-users] mythbackend stability on SMP systems

[Jarod Wilson]

On Aug 7, 2009, at 12:24 AM, David George wrote:

> On 08/06/2009 10:31 PM, David Engel wrote:
>>
>> On Fri, Aug 07, 2009 at 08:49:49AM +0930, Iain Buchanan wrote:
>>
>>> On Thu, 2009-08-06 at 17:11 -0500, David Engel wrote:
>>>
>>>> I would now like to make use of that extra CPU power, so I'm  
>>>> curious
>>>> how stable mythbackend, both 0.2 and trunk, is these days on SMP
>>>> hardware.
>>>>
>>> I'm running a single front-end back-end together on a P4 HT 3.0GHz
>>> laptop using a USB DVB-T HD tuner.  I've never had any problems with
>>> segfaults, although I'm still setting it up so it doesn't get too  
>>> much
>>> use yet.
>>>
>>
>> With only one tuner, your chances of having a problem are fairly low.
>> In my experience, the most vulnerable times were when multiple tuners
>> and jobs were starting or stoping at the same time.
>>
>> No one has responded with problems so perhaps things have gotten
>> better and I should give it another try.  Thanks to all who  
>> responded.
>
> I have been running exclusively SMP kernels since the non-SMP/SMP  
> kernel merge back in 2.6.16 (or was it 2.6.18).  Anyway, I had a few  
> issues with SMP back when I working on 2.6.9, but since 2.6.18  
> everything has worked well, except for a couple of regressions in  
> the XFS filesystem somewhere in the early 2.6.20's I believe.  I  
> switched to JFS, but I've heard XFS is working well these days also.

Yup, XFS is much happier now. In no small part, thanks to a fellow  
MythTV user, actually -- Eric Sandeen, a co-worker of mine here at Red  
Hat who works in our filesystems group (and before that, worked on xfs  
as an SGI employee). :)

> I run many tuners.  Since switching to SMP kernels exclusively I  
> have run (2) Air2PC ATSC cards with (3) PVR-250, until I swapped  
> them out for (2) HDHomeRun with (2) PVR-500.  I have just started  
> reconfiguring my backend again keeping the (2) HDHomerun and using  
> HD-PVR instead of the PVR-500's.  All of this was on the primary  
> backend.  I have also run with Fusion HDTV PCI and USB adapters,  
> pchdtv HD2000 and HD3000, PVR-150, and PVR-USB2 and probably others  
> that I am forgetting.  Needless to say I hammer on it pretty good.

Likewise, Typically at least 3 tuners in my smp backend box, plus an  
HDHomeRun, dating back several years now.

> This is all currently running trunk 21049.  I tend to update trunk  
> every couple of weeks unless I see something really interesting and  
> I update sooner.

Also running trunk here, updated every one to four weeks or so.

-- 
Jarod Wilson
jarod at wilsonet.com