Crazy slow Frontend startup and GUI interaction

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jgmtfia
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Crazy slow Frontend startup and GUI interaction

Post by jgmtfia » Thu Aug 27, 2020 5:48 am

I have a Pi 4 w/ 8 GB RAM and have made the recommended tweaks to the OS / myth config as per the Wiki for 0.31.

One oddity I have is that the general operation of the FE GUI. From the CLI or a window manager the GUI is crazy slow - about 20 seconds to get to the first GUI content from startup, DB / Backend connection takes 30 seconds (with little to no network traffic occurring) and opening a menu option or other GUI actions are laggy in the 5-10 second range.

When I check top, and network traffic the system, including the FE process, is basically dormant and I get snappy response via SSH or in the window manager while the FE just meanders along. I didn't do a lot with strace, but it seemed to be just sitting waiting for input on fd3 and 52 (which was kblockd)

The one wildcard about this setup is that the BE is across a IPSEC VPN. I have 400 Mb/s down and 30 Mb/s up cable connection and the connection is generally stable and consistent. Could the added VPN network latency cause such long delays? I am remote so I cannot test on the LAN the BE is on.

Video playback runs fine for ~8 seconds, then begins to stutter, and never recovers. I have been using PLEX without network issues but miss my 13+ year old myth setup so I was hoping to get the PI FE up... I did try to run the FE under ESX on a desktop CPU but PCI pass-true never worked on my intel config (would work on AMD) and now with ~ ESX 6.7 they have disabled IOMMU passtru so that path is also dead. 8(

Ideas welcome.

jgmtfia
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Re: Crazy slow Frontend startup and GUI interaction

Post by jgmtfia » Wed Sep 09, 2020 7:21 pm

It definitely seems to be the database link RTT for each query (~128-150 ms each). I tried a FE on a desktop computer with a known good compile of 0.31 and had the same issue.

Would a remote BE solve this issue? I have never setup a remote BE, so am not sure if the clients connect to the remote's database and the database between the BE's is replicated in some way.

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pgbennett
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Re: Crazy slow Frontend startup and GUI interaction

Post by pgbennett » Wed Sep 09, 2020 9:32 pm

A slave backed will not help. Slave backends use the same database, so the database would still be remote.

You could copy your entire mythtv setup including recordings to a laptop before you leave home and watch it wherever you may be. I have done that before.

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