Mailing List Archive: MythTV: Dev

EPG Slow

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bhuffman at graze

Sep 6, 2007, 8:51 AM

Post #1 of 8 (1302 views)
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EPG Slow

All,

I recently upgraded from SVN 13713 to SVN 14385 and have noticed that scrolling or jumping to a channel in the EPG is unbearably slow. I am running on a P4 2Gig w/ latest Fedora 6 updates. I have an Nvidia 5200 card using VGA out and (apparently from the logs) using "Video timing method: USleep with busy wait." I'm running the Mythcenter-wide theme using a screen mode of 1360x765. I also have the OpenGL painter in use (instead of Qt).

I've tried switching to normal mythcenter (not wide), turning off the opengl painter and switching to qt, and none of these seem to make a difference.

I have another system that is fairly different hardware: AMD with nvidia 440MX using the legacy binary drivers using svideo out and standard def mythcenter. It's running the same rev of SVN and connecting to the main server and it does not exhibit this behavior. I just checked and it's also using USleep with busy wait.

Can anyone point me in a direction to assist in troubleshooting this?

Thanks,
Brian

mtdean at thirdcontact

Sep 6, 2007, 9:43 AM

Post #2 of 8 (1257 views)
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Re: EPG Slow [In reply to]

On 09/06/2007 11:51 AM, Brian C. Huffman wrote:
> I recently upgraded from SVN 13713 to SVN 14385 and have noticed that scrolling or jumping to a channel in the EPG is unbearably slow. I am running on a P4 2Gig w/ latest Fedora 6 updates. I have an Nvidia 5200 card using VGA out and (apparently from the logs) using "Video timing method: USleep with busy wait." I'm running the Mythcenter-wide theme using a screen mode of 1360x765. I also have the OpenGL painter in use (instead of Qt).
>
> I've tried switching to normal mythcenter (not wide), turning off the opengl painter and switching to qt, and none of these seem to make a difference.
>
> I have another system that is fairly different hardware: AMD with nvidia 440MX using the legacy binary drivers using svideo out and standard def mythcenter. It's running the same rev of SVN and connecting to the main server and it does not exhibit this behavior. I just checked and it's also using USleep with busy wait.
>
> Can anyone point me in a direction to assist in troubleshooting this?

Sounds like missing/inaccessible (though specified in the DB) channel icons.

Mike
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bhuffman at graze

Sep 6, 2007, 10:01 AM

Post #3 of 8 (1243 views)
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Re: EPG Slow [In reply to]

Michael T. Dean <mtdean [at] thirdcontact> wrote:
>
> On 09/06/2007 11:51 AM, Brian C. Huffman wrote:
> > I recently upgraded from SVN 13713 to SVN 14385 and have noticed that scrolling or
> > jumping to a channel in the EPG is unbearably slow.  I am running on a P4 2Gig w/ latest
> > Fedora 6 updates.  I have an Nvidia 5200 card using VGA out and (apparently from the logs)
> > using "Video timing method: USleep with busy wait."  I'm running the Mythcenter-wide theme
> > using a screen mode of 1360x765.  I also have the OpenGL painter in use (instead of Qt).
> >
> > I've tried switching to normal mythcenter (not wide), turning off the opengl painter and
> > switching to qt, and none of these seem to make a difference.
> >
> > I have another system that is fairly different hardware:  AMD with nvidia 440MX using the
> > legacy binary drivers using svideo out and standard def mythcenter.  It's running the same
> > rev of SVN and connecting to the main server and it does not exhibit this behavior.  I just
> > checked and it's also using USleep with busy wait.
> >
> > Can anyone point me in a direction to assist in troubleshooting this?
>
> Sounds like missing/inaccessible (though specified in the DB) channel icons.
>
> Mike

That is the only thought that I had based on previous posts that I'd seen. It doesn't jive though b/c nothing has changed as far as the location of the icons (or the DB) and there are some icons showing up. I never had icons populated for all channels anyway, but I think that the ones that I had are showing up in the EPG.

In addition sometimes when I do a PAGEUP or PAGEDN, it will actually move the channels column (on the left) and then there'll be a long pause before it updates the actual guide data block. Although in general, any action is slow.

-b

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lists at wildgooses

Sep 7, 2007, 2:55 AM

Post #4 of 8 (1254 views)
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Re: EPG Slow [In reply to]

> Can anyone point me in a direction to assist in troubleshooting this?

If it's the guide grid itself which is slow then be sure to turn on
MYSQL query caching.

Ed W
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bhuffman at graze

Sep 7, 2007, 6:11 AM

Post #5 of 8 (1236 views)
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Re: EPG Slow [In reply to]

Ed W <lists [at] wildgooses> wrote:
>
> > Can anyone point me in a direction to assist in troubleshooting this?
>
>
> If it's the guide grid itself which is slow then be sure to turn on
> MYSQL query caching.
>

Already doing that assuming that setting the cache size implies that it's on. Here's a snippit from my.cnf:

key_buffer = 16M

table_cache = 128

sort_buffer_size = 2M

myisam_sort_buffer_size = 8M

query_cache_size = 16M

I don't think that the hard drive is even running when it's being slow, so it doesn't seem like it's thrashing.

I'll spend some more time this weekend. It's just confusing b/c this
wasn't happening before my last SVN update. But it has been quite some
time, so I guess a lot of things have changed.

Thanks,

-b

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willyboyd at gmail

Sep 7, 2007, 7:32 AM

Post #6 of 8 (1252 views)
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Re: EPG Slow [In reply to]

On 9/7/07, Brian C. Huffman <bhuffman [at] graze> wrote:
> I'll spend some more time this weekend. It's just confusing b/c this
> wasn't happening before my last SVN update. But it has been quite some
> time, so I guess a lot of things have changed.
>

Please do post back if you find out your specific cause. I'm
experiencing the same thing (noticing the channel column move
independent of the listings area), but haven't had the extra time to
troubleshoot. I'll be looking into the channel icon suggestion, too.
I already have similar mysql tuning params as you.

Willy
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xanium4332 at googlemail

Sep 7, 2007, 4:14 PM

Post #7 of 8 (1225 views)
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Re: EPG Slow [In reply to]

On 07/09/07, Willy Boyd <willyboyd [at] gmail> wrote:
>
> On 9/7/07, Brian C. Huffman <bhuffman [at] graze> wrote:
> > I'll spend some more time this weekend. It's just confusing b/c this
> > wasn't happening before my last SVN update. But it has been quite some
> > time, so I guess a lot of things have changed.
> >
>
> Please do post back if you find out your specific cause. I'm
> experiencing the same thing (noticing the channel column move
> independent of the listings area), but haven't had the extra time to
> troubleshoot. I'll be looking into the channel icon suggestion, too.
> I already have similar mysql tuning params as you.
>
> Willy

Just another 'me too' comment. The problem started as soon as I upgraded to
the latest -vid branch (from an earlier copy), which means it's also been
synced into the -vid branch. Unfortunatly I can't remember the exact
revision number, but I know that's what caused it as it was working fine
before the upgrade.

bhuffman at graze

Sep 7, 2007, 5:21 PM

Post #8 of 8 (1215 views)
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Re: EPG Slow [In reply to]

On Sat, 2007-09-08 at 00:14 +0100, James Buckley wrote:
> On 07/09/07, Willy Boyd <willyboyd [at] gmail> wrote:
> On 9/7/07, Brian C. Huffman <bhuffman [at] graze> wrote:
> > I'll spend some more time this weekend. It's just confusing
> b/c this
> > wasn't happening before my last SVN update. But it has been
> quite some
> > time, so I guess a lot of things have changed.
> >

Ok...I found something although I don't know what to make of it.

1) If I do a mythfrontend -v database, it does appear that there's a
pause after doing the select for the channel icons (take a look at the
timestamp between the icon and the next select):

2007-09-07 19:52:36.121 MSqlQuery: SELECT icon FROM channel WHERE chanid
= '2571' ;
2007-09-07 19:52:41.424 MSqlQuery: SELECT DISTINCT program.chanid, program.starttime, program.endtime, program.title, program.subtitle,
<snip>

HOWEVER! The icon exists and does indeed display. Which is why I'm
confused.

2) Ok....here's the next tidbit:

If I run an strace -f -p <mythfrontend pid> -tt -e trace=file while
running the frontend, then the guide traversal speeds up
significantly!

Take a look at this difference:

2007-09-07 20:00:39.974 MSqlQuery: SELECT icon FROM channel WHERE chanid
= '1166' ;
2007-09-07 20:00:40.457 MSqlQuery: SELECT DISTINCT program.chanid,
program.starttime, program.endtime, program.title, program.subtitle
<snip>

Not even a full second. And you can see the corresponding access in the
strace:

[pid 3356] 20:00:39.976855
access("/usr/share/mythtv/themes/MythCenter-wide/", F_OK) = 0
[pid 3356] 20:00:39.977304
open("/usr/share/mythtv/themes/MythCenter-wide/", O_RDONLY|O_LARGEFILE)
= 29
[pid 3356] 20:00:39.983121
open("/home/mythtv/.mythtv/channels/vh1.jpg", O_RDONLY|O_LARGEFILE) = 29
[pid 3356] 20:00:40.033220
open("/home/mythtv/.mythtv/channels/tnn_30.jpg", O_RDONLY|O_LARGEFILE) =
29
[pid 3367] 20:00:40.147140 open("/dev/hdd", O_RDONLY|O_NONBLOCK|
O_LARGEFILE) = 29
[pid 3367] 20:00:40.159873 open("/dev/hdd", O_RDONLY|O_NONBLOCK|
O_LARGEFILE) = 29

The only thing that I can think is that there's some sort of IO
bottleneck and the strace slows things down enough (since it has to
display to the screen) that the file access of the icon can succeed?
Anyone else have an idea?

Thanks,
Brian

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