[mythtv-users] prebuffering pause???

Mark Lehrer mark at knm.org
Tue Apr 17 22:09:02 UTC 2007


> the frontend log gets messages saying "prebuffering pause" ever 2-5
> seconds while Live TV is playing. I also occasionally get a message
> saying "Prebuffer wait timed out 10 times."
>
> Is this normal or is this an indication that something is wrong with my
> setup?


This is definitely not good.  I used to get this when the system was
recording hi def content and trying to play something back at the same
time.  It had to do with the write cache buffer timings.  It was
waiting too long to write out the new recording, and when the write
cache timed out after 30 seconds or so it would pause all disk access
for a few seconds.  Extremely annoying!

In my case, I had to adjust the following:

/proc/sys/vm/dirty_background_ratio
/proc/sys/vm/dirty_expire_centisecs
/proc/sys/vm/dirty_ratio
/proc/sys/vm/dirty_writeback_centisecs


I did this by adding the following to /etc/sysctl.conf:

vm.dirty_expire_centisecs = 300
vm.dirty_writeback_centisecs = 50


This solved the problem perfectly for me.

Good luck,
Mark


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