View unanswered posts    View active topics

All times are UTC - 6 hours





Post new topic Reply to topic  [ 12 posts ] 
Print view Previous topic   Next topic  
Author Message
Search for:
PostPosted: Thu Mar 11, 2004 7:55 pm 
Offline
Joined: Fri Feb 27, 2004 10:58 pm
Posts: 129
Hi all,
After reading through the Mythtv news letters for couple days, I've seen a lot of people talking about using XFS for their LiveTV cache. They said that supposely XFS has really fast file delete. Since when you change channel, Mythtv Delete the old cache ring file and then change channel, faster file delete makes faster channel change. Want to try it up, I took the plunge tonight after making sure with Cesman that it won't have trouble with R4V2.

Below is what I did. (part of it is from Jarod's Fedora MythTV how-to)

exit from mythfrontend

su to root

"mount"

(make sure you know what partition the /cache is mounted from)

"umount /cache"
"/sbin/mkfs -t xfs -f /dev/hda3"
(my cache is mount from /dev/hda3. default auto-install from KnappMyth)

edit /etc/fstab

I change the line
"/dev/hda3 /cache auto defaults,auto 0 2"
to
"/dev/hda3 /cache xfs defaults,auto 0 2"

(I am not sure if this part is necessary since "auto" should auto detect what file system it is, but then again I am sorta a linux newbie so i dont want to screw things up)


"mount /cache"
"mkdir /cache/cache"
"chown mythtv:mythtv /cache/cache"

now try to launch mythfrontend
If you get the message of not able to connect to the backend server, just restart it. "/etc/init.d/mythtv-backend restart"

I was able to shave about 1 second off for channel switching. (it went from about 2~3 seconds to about 1~2 seconds)


Top
 Profile  
 
 Post subject:
PostPosted: Sat Mar 13, 2004 5:32 pm 
Offline
Joined: Wed Mar 10, 2004 6:40 pm
Posts: 54
Has anyone else tried this? It sounds like an easy change for a big payoff.


Top
 Profile  
 
 Post subject:
PostPosted: Sat Mar 13, 2004 9:39 pm 
Offline
Joined: Tue Feb 24, 2004 9:00 am
Posts: 5
The change is easy enough to make. I left the setting in fstab to auto and it was detected as xfs. With Grooby's instructions it can be accomplished in under 5 minutes.

Using the very unscientific one-Mississippi, two-Mississippi method of timing, I found that prior to the change I was able to make it fully through three-Mississippi before the channel would change.

After the change I make it to "three" but don't get the Mississippi out before the change takes place.

Despite the fact that I tested several times before and after the change I cannot vouch for the accuracy of my methods.

I'm curious to hear what others say.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Mar 14, 2004 8:34 am 
Offline
Joined: Wed Mar 10, 2004 6:40 pm
Posts: 54
Well, I took the plunge and these are my results

Before making the change it took 58 seconds to go throguh my entire chanel lineup.

After making the change it took 58 seconds to go through my entire chanel lineup.

Before 58 sec, after 58 sec

Clearly not worth the effort...... Oh well,


Top
 Profile  
 
 Post subject:
PostPosted: Sun Mar 14, 2004 8:48 am 
Offline
Joined: Fri Feb 27, 2004 10:58 pm
Posts: 129
took you 58 seconds?!?!?!?!?!
OMG!!!! what is your system setup?!?!


Top
 Profile  
 
 Post subject:
PostPosted: Sun Mar 14, 2004 9:22 am 
Offline
Joined: Mon Nov 17, 2003 8:59 am
Posts: 206
Location: Michigan
I think he's saying it took that long to flip through all the channels. I never flip though anymore, just use the guide. Atomclock, did you just do that to test the before/after, or do you really do that?


Top
 Profile  
 
 Post subject:
PostPosted: Sun Mar 14, 2004 10:28 am 
Offline
Joined: Mon Oct 06, 2003 10:38 am
Posts: 4978
Location: Nashville, TN
I might could see 58 sec to scroll through the menu, but no way 58 sec to switch through all off the channels unless you only have like ota with about 10 channels.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Mar 14, 2004 10:51 am 
Offline
Joined: Wed Mar 10, 2004 6:40 pm
Posts: 54
I have 25 channels... And I waited for each to fully stablized before going to the next channel. Most of my channels are static because I use an antenna instead of cable. I wanted to get the box working berfore I committed to $47 + tax + etc per month for (extended-basic analog) cable. Comcast in DC is VERY expensive. Unfortunately, I don't have a south facing view from my appartment so I can't get sattelite TV.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Mar 14, 2004 11:00 am 
Offline
Joined: Mon Nov 17, 2003 8:59 am
Posts: 206
Location: Michigan
I wonder if the size of the ring buffer makes a difference here. Quick tests like this are quite different from destroying a ring buffer that's a gig or three in size.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Mar 14, 2004 11:09 am 
Offline
Joined: Wed Mar 10, 2004 6:40 pm
Posts: 54
Why don't some of you post your tests and methodologies. Since the motivation for changing the file system was to gain an improvement in chanel change performance, I thought my test was a valid test. But maybe it wasn't for example, I have two TV cards. The card I performed the test with was a PVR 350. Maybe I would have had different results using my other tuner the Bt878.

My system is currently configured as follows

- Epox 8K7A via chipset--I have had the capacitors replaced due to leakage
- AMD 1.2 GHz Athlon
- 256 MB ram I will probably upgrage to 512 MB
- Nvidia GForce
- Western Digital 160 GB drive
In slot order
1. PVR 350 (Tuner = 2)
2. cooling fan
3. cooling fan
4. Hercules Fortissimo II sound card
5. Hauppague TV card (Bt878 Revision (2))
6. Network card nt results using my


Top
 Profile  
 
 Post subject:
PostPosted: Sun Mar 14, 2004 1:30 pm 
Offline
Joined: Mon Nov 17, 2003 8:59 am
Posts: 206
Location: Michigan
Atomclock, I was not being critical, my point is that switching to xfs might not gain any speed if the size of the files being dealt with are only a couple of meg.

I haven't switched because a) my system is in production, b) I don't channel surf.
If the concensus is that this is a good idea, I'll do it some night after the family goes to bed. :)


Top
 Profile  
 
PostPosted: Sat Apr 17, 2004 10:33 pm 
Offline
Joined: Mon Mar 08, 2004 9:09 pm
Posts: 30
Location: SLC, UT, USA
Thanks for the XFS info, everyone. I don't notice it changing channels faster, but this information was a huge help since my system is now very much more stable. I installed since I was tired of a 5-15 minute fsck if I had to reset my system because of a lockup.

I used to have erratic problems with my recordings stopping in the middle. About every 3rd to 5th show I recorded would randomly die in the middle. It was really frustrating since Myth was not very dependable. I was also afraid to watch a recorded show, to access the myth schdule in a web browser, or to delete an old show while something was recording since it would often screw something up and my recording would stop.

As far as I can tell, changing the LiveTV partition and my recording drive to XFS has fixed all these problems completely (about 20 shows in a row without any problems). No more lockups or weirdness no matter if I watch something else while myth is recording, delete other programs or look at the schedule in a browser. XFS has worked miracles for my box.

In case anyone is interested: My Hardware: PIII 733, ABIT SE6 Motherboard, PVR350 tuner. It was my old computer and is now serving nicely as my PVR.

If I could only get the program guide over the live TV to NOT lock up my system every time, now. Oh well, it's not too essential and I have the feeling that better IVTV drivers will fix this problem when they get released.


Top
 Profile  
 

Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 posts ] 


All times are UTC - 6 hours




Who is online

Users browsing this forum: No registered users and 17 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group

Theme Created By ceyhansuyu