[CentOS] Desktop lag with CentOS7/Mate and high CPU usage

Thu Aug 2 16:43:26 UTC 2018
James Pearson <james-p at moving-picture.com>

James Pearson wrote:
> We have noticed significant desktop/UI lag on CentOS7 workstations using
> Mate when the CPU usage is high - i.e. the mouse pointer lags and moving
> windows (e.g. terminal windows) become jumpy (not smooth)
> We didn't see (or notice) this issue with CentOS6/Gnome2
> This can easily be shown by running something like 'cpuburn'
> (https://patrickmn.com/projects/cpuburn/) and moving a mate-terminal
> window around the screen
> We can make things 'better' by running CPU intensive apps via 'nice'
> (without any noticeable performance hit to the CPU intensive app) - but
> this is a rather messy way of fixing the issue
> We can also make things better by renice'ing X to a negative nice level
> However, both these approaches seem wrong to me - as I'm probably
> missing something straightforward here
> Does anyone know of any CentOS7/Mate settings that could be used to
> improve desktop/UI responsiveness with high CPU usage ?

Just to follow up on this - we think this issue _might_ be self 
inflicted ...

When we started moving users to CentOS 7 from CentOS 6, we had reports 
that things like opening shells, running scripts and similar non-CPU 
intensive everyday tasks were generally 'slower' - this turned out to be 
a result of the default 'tuned' policy ('balanced') using the 
'conservative' CPU governor setting (we didn't have any similar CPU 
throttling set up on CentOS 6) - and switching to the 
'throughput-performance' tuned policy 'fixed' this issue for us - as it 
uses the 'performance' CPU governor

However, it looks like something else in the 'throughput-performance' 
policy is causing (or contributing to) the desktop lag issues we've been 
seeing - and switching to a custom tuned profile (based on 'balanced' 
but using the 'performance' CPU governor) appears to fix our desktop lag 
issues ...

James Pearson