[mythtv-users] Fixed: Choppy watching current recording.
TwoOneSix at thatclothingco.com
Fri Jan 26 18:51:58 UTC 2007
Billy Macdonald wrote:
> I just setup two HD Homerun devices and was having problems
> watchingrecording in progress. I was getting prebuffering pauses and
> top was showing 15-25% iowait.
> I could record four HD shows at once and watch a fifth prerecorded
> HD show and that was fine, it was only watching a recording in
> progress that was bad. I changed the NFS mount options from a rsize &
> wsize of 32768 to a rsize & wsize of 8192. This lowered the iowait
> times to around 4%. Playback of a recording in progress now works.
> I'm not quite sure why this made the difference as I have the
> network bandwidth since watching a HD recording while four others are
> being recorded shows an iowait of 0% and no problems at all.
> Myth-0.20-fixes. Maybe the it was the file access in 32k chunks that
> was the problem?
> My frontend and my two hdhomeruns connect to a 1G switch to another 1G
> switch to the backend as attempted to diagram below.
> Frontend -- 1G --
> HDhomerun --100 -- Dlink -- 1G -- Dlink -- 1G -- Backend
> HDhomerun -- 100 --
> I couldn't find much info troubleshooting this but after the fix I
> noticed that 8192 is the suggested value in the setup docs, so I guess
> it's there for a reason.
> mythtv-users mailing list
> mythtv-users at mythtv.org
You know what's funny is that I was posting to the "Jittery playback"
thread a few nights ago and I discovered that my "jittery playback"
issue went away after I reconfigured my NFS shares in this EXACT same way:
<mythserver>:/video /video nfs rsize=8192,wsize=8192
Now I don't have the "jittery playback" even on my wireless frontend
machine anymore! I had initially made that change because I was having
issues connecting my NFS shares (I discovered that if a sub directory
you want to share VIA NFS resides on a separate physical disk that you
have to explicitly share it VIA the /etc/exports file or the directory
appears to the remote client as empty) I had my /video directory shared
and thought it would include the /video/dvds directory but since I
currently map my /video/dvds directory to a Seagate 500GB SATA disk, it
didn't show up. I beat my head against the wall for 2 days until I
figured that out. Anywho, when I was reading up on NFS shares they all
said for optimum NFS performance to set the r/wsize to 8192 (I didn't
previously have it set at all) I didn't even put the 2 together until I
read this post and now it all makes sense.
Wow, as many times as I tell people to RTFM I guess I should have taken
the advice for myself for one. :-)
P.S. I made this message long and winded to try and catch search terms
of others that might find this post helpful while searching the archives
for this issue.
More information about the mythtv-users