[mythtv-users] Re: Shuttering video in myth

Axel Thimm Axel.Thimm at ATrpms.net
Sun May 29 08:17:20 UTC 2005


On Sat, May 28, 2005 at 11:06:24PM -0700, Fedor Pikus wrote:
> I'm mostly done putting together the myth box, but I ran into a
> problem I did not expect, not with the hardware I put together: video
> playback is stuttering quite badly. It does not happen all the time,
> but mostly in these two cases:
> 1) After I switch channels in live tv, there is a pause (expected),
> then it starts playing, pauses, resumes, does it several times, this
> lasts for 10-20 seconds, then it starts playing ok.
> 2) If I pause live tv and then play it after a while, video stutters
> and pauses, and it gets worse the longer I wait. If I paused for an
> hour, it'll be impossible to watch, it'll halt every few seconds for
> half a second, and unlike the case above, there is no end to this.
> 
> I'm running FC3, 2.6.11 kernel, latest myth and ivtv from atrpms (myth
> 0.18.1-111, ivtv-0.3.5l-92).
> The box is built around Soyo Dragon2 motherboard, Athlon 3200+ CPU,
> 2GB of dual-channel RAM.
> 
> When video stutters, I often see disk light come on, especially in the
> second case, so here is more about disks. There are 4 Seagate 300GB
> ATA disks in the box, with two software RAIDs:
> 
> /dev/md0 mounted as /, raid1 built from hdb1, hdc1, 20GB, ext3
> /dev/md1 mounted as /raid and used for all mythtv files, raid5 built
> from hdb3, hdc3, hde3, hdf3 (currently runs in degraded mode until I
> add 5th disk), about 1TB, JFS.
> hdX2 are swap partitions, 1G on each disk, striped.
> 
> Seems like I need to tune the system for beter I/O performance. Any tips?

Could you check the relevant folders (/raid) with bonnie++?

	  http://atrpms.net/name/bonnie++/

Is the live buffer also under /raid?
-- 
Axel.Thimm at ATrpms.net
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