[mythtv-users] Dual-FireWire troubles in 0.20 solution found

Michael T. Dean mtdean at thirdcontact.com
Fri Sep 15 22:26:53 UTC 2006

On 09/15/06 17:07, Yeechang Lee wrote:

>Michael T. Dean <mtdean at thirdcontact.com> says:
>>In other words, you said the max (96256) worked on previous
>>versions.  You know that you had issues with the default value
>>(which is now 4700--and is also the min).
>Never said that.
Oh, so you were just changing values in 0.18 randomly ( 
http://www.gossamer-threads.com/lists/mythtv/users/184085#184085 ).  I 
stand corrected.  I guess we only have one data point, now.

> The maximum setting got inherited when I upgraded to
>0.20; I never touched this setting during the upgrade because I hadn't
>changed it in about eight months.
>>But your system requires 23.5MB, so 96MB is overly large.
>If the setting--remember, it isn't a free-entry field, but essentially
>Myth's equivalent to a dropdown box--lets me go up to a certain level,
>and there are no warning messages about it,
HD Ringbuffer size (KB)
The HD device ringbuffer allows the backend to weather moments of 
stress. The larger the ringbuffer, the longer the moments of stress can 
be. However, setting the size too large can cause swapping, which is 

> and good reason to believe
>that "bigger = better,"
If that were always the case, why wouldn't Myth use bigger for the 
default?  Currently, it uses the minimum value for the default.

> and it's been working fine for months, and a
>software upgrade breaks this behavior, that's the sign of a bug. It is
>not the sign that that setting is ipso facto "overly large."
>>Which doesn't seem to be enough for 2 firewire captures running with 
>>96MB ringbuffers each.
>Another non sequitur. You know very well how much (little) a backend
>needs for RAM. One more time:
>* 0.19 did not have this issue.
>* 0.20 does; thus something broke.

Only if you can prove that 96MB is the proper configuration is this a 
sign of a bug in 0.20.  An upgrade causing an incorrect configuration to 
show problems isn't a sign of breakage in 0.20, but a sign of brokenness 
of previous versions.


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