[mythtv-users] mythtv causing 100% CPU and 75 % memory load since last upgrade

Peter Bennett cats22 at comcast.net
Mon Feb 6 03:42:13 UTC 2017

On 02/05/2017 04:01 PM, Johannes Rohr wrote:
> So I have downgraded mythtv to version 1:0.28-6, but this makes no 
> difference, mythbackend causes 100% CPU load and uses 75% of memory 
> until it eventually gets killed by the kernel. Any tips how to 
> investigate this? I thought I might begin by emptying the database 
> (after backing it up), but I'd really like to know what might be 
> causing what seems like a memory leak.
> Am Sonntag, den 05.02.2017, 18:57 +0100 schrieb Johannes Rohr:
>> Dear fellow users,
>> I am running mythbackend on a Raspberrypi 3 on Arch Linux Arm. Until
>> today's upgrade to version 1:0.28-9, it has been running smoothly.
>> Since I ran pacman -Suy today, mythbackend is constantly using 100% CPU
>> time and uses most of memory, at the moment 75%.
>> Unfortunately, there is nothing in the log which seems unusual. Even if
>> I run mythbackend with --loglevel=debug, I don't see any information
>> coming out of it, after the usual startup messages.
>> So I have absolutely no idea what is wrong here.
>> What I am seeing now seems too unspecific even for a bug report to
>> Archlinuxarm, can anybody recommend what I can do to extract
>> information, or can someone say what know causes for this kind of
>> behaviour are?
>> Cheers, thanks!
>> Johannes

Do you compile your own MythTV for Arch Linux on Raspberry pi?

Since I have no experience with a backend on raspberry pi, I do not know 
what the normal performance may be. How much CPU time was it using 
before? Maybe it was using 90% before and now is using 100%? Using 75% 
of memory also may not be unusual, since the Raspberry Pi only has 1 GB 
of main memory.

Maybe the new version of Arch Linux is 64bit and the old version was 32bit?

How do you connect tuners to the raspberry pi, and what do you do for 

One thing I have noticed is, if you run a frontend on a raspberry pi 
with a hard drive attached, it seems to spend a lot of time scanning the 
hard drive. It works better with only an SD card. There may be some 
issues like this with a backend.


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