[mythtv-users] Mythvideo performance

[Michael T. Dean]

On 06/15/2006 12:20 PM, Ryan Steffes wrote:
> Those of you with long memories for detail may know that I have 
> constant struggles with my MythTV's performance, usually for no 
> apparent reason.  I have no great reason for my machine to be 
> sluggish, but none the less, it likes to taunt me.  I'm pretty sure my 
> myth computer hates me.  My current issue is two-fold, going into My 
> Videos has a noticable delay.  I assume it's because I have a several 
> hundred videos ( recently finished ripped my entire DVD collection to 
> the machine).   I open mythvideos in gallery mode.

What's noticeable mean to you?  One or two seconds, or 5 seconds, or 10 
seconds, or ...

> My current set up:
> I've currently got a combine frontend/backend with a 400G video 
> partition spread across two drives using LVM.  It's a reiserfs partition.
...
> As stated, there's approximately 350 video files.  Gallery mode is 
> important to me, for WAF.  She and I like to see the videos with 
> covers laid out as they might be on the shelf, and have it set to 
> display 8 at a time, which makes it easier to find a movie

I get a noticeable delay of less than 2 seconds when entering into 
gallery view on my combined frontend/backend with 244 videos, but it's 
almost completely from reading the images for the 8 video posters I 
display per screen.  (In other words, my setup is almost identical to 
yours, and what's left of the performance problem is not inside Myth.)

If entering the list view (loaded from the database--not from the 
filesystem) is fast, loading the posters is the (non-Myth) problem 
causing the delay.  If not, it could be the sorting or something else...

Make sure you disable the setting:

Video List browses files
If set, this will cause the Video List screen to show all relevant files 
below the MythVideo starting directory whether they have been scanned or 
not.

for the test.  Note, also, that there's an equivalent setting for the 
other 3 views.

> Also, I don't know if this is a problem or just an oddity, when I go 
> to play a movie, it kicks off two mplayer processes.

Probably a bad player command...

>
> Any suggestions for how to improve the performance?  I've considered 
> going to a difference file system, but I'm not sure it'll help.  I 
> seem to have performance issues in general, which doesn't make a ton 
> of sense for only having one PVR150 and one frontend, even running off 
> two ATA100 drives.  I still get the occasional lock up on this 
> machine, seemingly related to my ethernet driver, and I'm wondering if 
> going to a new flavor of linux, such as gentoo, would help.  I'm 
> running Mandriva now, 2.6.12-12mdk.  I'm loathe to figure out how to 
> migrate that much data when I don't have a spare drive around.  
> Growing an XFS file system a dozen times to move the data just seems 
> like asking for trouble. 

Since [6646] (which is part of MythTV 0.19, but not part of MythTV 
0.18), MythVideo does an in-memory sort of videos to allow for removal 
of the initial articles (A |An |The ).  This causes some problems, so I 
wrote some patches to fix it, in #1354--which was committed in 
[9694]--and #1678--which is not committed.  The patch in #1678 would 
remove the in-memory sort from MythVideo (while allowing you to specify 
the sort key for each video).

Also, in #1569, George Nassas wrote a patch which was made to speed up 
his MythVideo.  I don't know anything about the details of this patch, 
and I haven't used it, so I don't know how much it would help you (it 
still does an in-memory sort, but it makes other changes to speed things 
up).

However, some of the changes in #1569 are incompatible with #1678.  
Therefore, you'd have to choose one or the other (or merge the changes).

That being said, if you're compiling Myth yourself, you can apply one of 
these and see if it helps.  If you're not compiling Myth, it will be 
hard to determine if the problem is inside Myth or outside...

#1678 - http://svn.mythtv.org/trac/ticket/1678 - use the patches 
*-mythvideo-titlesortkey_in_database.patch (but use 
mythplugins-mythvideo-titlesortkey_in_database-2.patch for 
mythplugins).  Note that this will change your video database schema, so 
if it's not accepted (or accepted after another change to the video 
database schema), you'll have to manually fix the database.

#1569 - http://svn.mythtv.org/trac/ticket/1569 - the current patch is 
grabbag-2.diff.gz , but George will have to help you with it.

Mike