[mythtv-users] Cheapest way to build a frontend?

Marco Nelissen marcone at xs4all.nl
Wed Dec 27 00:28:35 UTC 2006

>Marco Nelissen wrote:
>> I agree, it *should* be able to deal with this. Have you tried to isolate
>> the problem by measuring disk throughput, network throughput and CPU usage
>> while doing so? Are you using XvMC?
>It seems that the disk throughput is the problem. I get 20-66 MB/s when 
>watching TV, as measured by "hdparm -tT /dev/sda" whereas others get 
>200-300 MB/s. I get that much when idling only. No XvMC, and CPU is 
>consistent with what others get (I am not at home right now.)

Are you sure about that "200-300 MB/s"? That seems awfully low for it
being the "cached reads" result (which doesn't actually hit the disk),
and awfully high for the "buffered disk reads" result on a single-disk
(or even two-disk raid) configuration.
I'm getting 1300 MB/sec cached reads (which don't actually hit the disk)
and around 65 MB/sec buffered disk reads (which does read from disk)
when the system is mostly idle. My system is somewhat similar to yours:
a combined front/back end with an Athlon64 3200+, 512MB RAM, nVidia FX5200,
250 GB SATA disk. I do have XvMC enabled though.
When I run 'hdparm -tT' while playing back HD in mythtv, I get between
6 and 15 MB/sec for the buffered disk reads. I can play another HD
stream shared over SMB to another machine without trouble while playing
the one in mythtv, and both play smoothly. If I run hdparm -tT while
playing both, I get around 3.5 MB/sec. While running hdparm video does
stutter a little.

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