v17 Trying to nail down some NFS performance issues
#1
Hey everybody,

I'm hopefully after some input to try and help me nail down a few performance issues I'm having with watching TV shows or Films in Kodi.

It's not really support per se I'm after more an answer to some questions I have about the way Kodi mounts NFS shares and whether or not I'm correct in thinking it will affect throughput.

Bit of background, ignore if you just want to get to the question:

I have 5 Nas's sharing ripped media (Bluray and DVD), some transcoded and some re-muxed, to numerous installs of Kodi (V16 & 17) around the house on pretty much every OS Kodi runs on. All the media is shared over NFS (a hangover from my Popcorn Hour C200 days when you couldn't play a Bluray rip over SMB).

Up until recently this has worked perfectly (except when user error is involved). Now however on my Kodi V17.0 installs (one on an Nvidia Shield Tablet and one on a Surface Pro 4) I'm getting microstutters and drifting audio sync when trying to watch anything, every so often, normally towards the end of a TV episode, the video will just freeze for 5-10 seconds before carrying on again. I haven't noticed the freezing on any films but I don't tend to watch many and very rarely sit down and watch one in one sitting so I might just not have let one play for long enough to exhibit the problem.

The NAS's are running Netgear ReadyNAS 6.5.1 or Synology DSM 5.2 and on both NFS rsize and wsize are set to 32768.

And so to the questions (kind of):

The debug log from both devices shows

Code:
00:14:51.448 T:18446744071726221600   DEBUG: NFS: Context for 192.168.0.11/volume1/Video not open - get a new context.
00:14:51.511 T:18446744071726221600   DEBUG: NFS: Connected to server 192.168.0.11 and export /volume1/Video
00:14:51.512 T:18446744071726221600   DEBUG: NFS: chunks: r/w 131072/131072
00:14:51.592 T:18446744072073775392   DEBUG: ffmpeg[9E800920]: [swscaler] No accelerated colorspace conversion found from yuv420p to bgra.

The questions are, where does Kodi get the rsize and wsize of 131072 from? Why is it so much higher than the server is set to? Will this cause an issue with performance? Am I barking up the wrong tree?

I unfortunately didn't have debug logging enabled before now so I don't have one of any issues with the media (and it's too late to watch anything now) I just enabled debug logging on my two tablets and checked them to see if anything obviousl jumped out at me as being an issue first and that was the only thing that jumped out at me.

I am quite happy to post the two logs if anyone wants them though I'm really only after an answer to the questions I'm quite happy to continue troubleshooting myself.

I'm going to get some more logs on Monday when I have some time to sit down and watch something and I'll be configuring a few of the Kodi 16.0 devices for debug logs tomorrow (well later today really I suppose it is 02:30...) and comparing those to see if I can see why they're not exhibiting the problem. I'll quite happily post those if anybody wants them as well.

TL/DR: Where does Kodi get it's NFS rsize and wsize from and will them being different to the server cause a problem?

Thanks for any input Smile

Mnementh
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#2
Normally the rsize and wsize is queried from the server and the wsize is also limited to 32k (can't remember the reason but thats only used for writing anyway). The read chunksize is unused currently. Afaik nothing in the nfs implementation has changed between kodi 16 and 17 - but the used libnfs might have gotten an update between releases (you could try copying the libnfs.dylib from kodi 16 to kodi 17 and check if it changes anything)
AppleTV4/iPhone/iPod/iPad: HowTo find debug logs and everything else which the devs like so much: click here
HowTo setup NFS for Kodi: NFS (wiki)
HowTo configure avahi (zeroconf): Avahi_Zeroconf (wiki)
READ THE IOS FAQ!: iOS FAQ (wiki)
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#3
Thanks Memphiz,

That was something I didn't think of trying as I would have thought the code would have checked for specific versions of libs but it's definitely worth a try.

As soon as the rugby has finished on the Telly I'm gonna commandeer the living room TV for a bit to turn debugging on the firestick and get someone to watch a few programmes. Can start comparing between the two versions then see if anything obvious jumps out.
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