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| Dual Processor http://forums.linhes.org/viewtopic.php?f=17&t=4830 |
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| Author: | bgsneeze [ Tue Jun 07, 2005 8:34 am ] |
| Post subject: | Dual Processor |
Will MythTV or KnoppMyth take atvantage of dual processors? I have a dual 866 Pentium III that I wqould like to use as a VCR, only recording one program at a time, it would not be running live TV. |
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| Author: | Xsecrets [ Tue Jun 07, 2005 8:36 am ] |
| Post subject: | |
yes the default kernel is compiled with smp support. |
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| Author: | bgsneeze [ Tue Jun 07, 2005 8:48 am ] |
| Post subject: | but what about the software? |
But what about the capture and display software? Just because the kernel is able to proform its functions on dual processors doesnt mean that MythTV will use both. I have run other software that was compiled/written for only one processer so the kernel processes saw a speed increase but the user program saw no increase. I am asking because this dual processor machine is free (as in beer) and i would like to make a good digital recorder.....By the way what capture card is recomended for a slow machine like this? |
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| Author: | wififun [ Tue Jun 07, 2005 8:59 am ] |
| Post subject: | |
grab one of the hardware encoder cards the pvr x50's would be your best bet. This will solve the capture problem, but on the slower machine playback may be an issue. I have had good playback of pvr250 content on an xbox, so your machine should be fine, even if it is only using one processor for the work. You could try a 350's video out, but know that that can take some work to configure. I believe the wiki has a how to. |
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| Author: | tjc [ Tue Jun 07, 2005 10:31 am ] |
| Post subject: | |
The back end and front end are entirely seperate processes, as are lircd, ... So even if the playback decoding is single threaded (I've never bothered to investigate) other stuff will be offloaded to the second CPU, so the answer to your question is, "YES, it will take advantage of multiple CPUs". |
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| Author: | Liv2Cod [ Tue Jun 07, 2005 11:40 am ] |
| Post subject: | |
For example, one of the tasks which is run in the background is "flagging" the commercials. Another is transcoding the shows from one format to another. Multiple CPUs will help in a number of ways. I'd say go for it. |
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| Author: | jeffskyrunner [ Tue Jun 07, 2005 8:23 pm ] |
| Post subject: | |
It would also help if you have the main Backend as a Samba server Also right? (dual 700 mhz p3s) |
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| Author: | bgsneeze [ Wed Jun 08, 2005 2:50 pm ] |
| Post subject: | |
well i only want one machine that captures and then plays back. If my understanding of dual processor programming is correct, the software must be written to be aware of the two processors, other wise programs will run only on the first processor (CPU 0). The kernel which has been written and compiled for dual processors will do its tasks of hardware control / memory management will run on both, but the user-space programs such as mythtv would need to be written and compiled for dual processors as well. If mythtv is written for dual processors that would lighten the load on my system. |
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| Author: | graysky [ Wed Jun 08, 2005 3:23 pm ] |
| Post subject: | |
Is anyone actually running a mythbox with dual processors? Seems like overkill to me. |
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| Author: | Xsecrets [ Wed Jun 08, 2005 5:08 pm ] |
| Post subject: | |
I don't know about that, but the smp kernel does take advantage of hyperthreading for people with PIV. |
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| Author: | tjc [ Wed Jun 08, 2005 7:34 pm ] |
| Post subject: | |
bgsneeze wrote: If my understanding of dual processor programming is correct, the software must be written to be aware of the two processors, other wise programs will run only on the first processor (CPU 0).
You're missing the fundamental point. This is Unix not the braindamaged nightmare from Redmond that set computer science back ten to twenty years. The MythTV "application" is actually made up of a number of cooperating programs, drivers, and daeoms which run more or less indepentantly (as seperate "processes") and communicate via some type of IPC (inter process communications) usually sockets. Even if the individual program modules are single threaded (and not all of them are) you're running MULTIPLE programs/processes which can easily take advantage of MULTIPLE CPUs. |
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| Author: | nigelpearson [ Thu Jun 09, 2005 4:51 am ] |
| Post subject: | |
bgsneeze, the mythtv programs use multiple threads, so yes they will benefit from a dual CPU motherboard. I think the frontend usually uses 6 threads when playing back a recording. If you are doing anything at the same time as watching TV (like using the mythburn scripts to create a DVD of recordings), dual CPUs will be _very_ helpful. |
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| Author: | bgsneeze [ Thu Jun 09, 2005 7:22 am ] |
| Post subject: | |
thank you |
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| Author: | steeve [ Thu Jun 09, 2005 9:34 pm ] |
| Post subject: | |
Quote: thank you
yes, guys, thank you. I'm in the early stages of building a dual 2.4GHz Xeon box as my backend. I did a lot of reading (a LOT of reading) about Myth, and was under the impression that Myth (or rather, MySQL) was heavily multi-threaded. In any event, your opinions have solidified my suspicions that a dual CPU box of respectable processing power might be a very good backend, especially if we consider HDTV... 
-Bob K. |
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| Author: | Greg Frost [ Thu Jun 09, 2005 10:28 pm ] |
| Post subject: | |
It's the frontend that needs the grunt when displaying hdtv, not the backend. |
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