A question regarding isolated cpus and software interrupts

Hi

My question isn't directly related to lttng but I would welcome some advice.

Our Linux application is showing 'blips' whereby there are occasional
increases in processing times. This is for a user process that runs on
an isolated core. Using lttng and TraceCompass I have found that the
'blip' sometimes coincides with a TIMER_SOFTIRQ event on the isolated
core.

I was surprised that software interrupts may run on isolated cores. Is
there a way of preventing this?

Are there any techniques using lttng to gain more information related
to the interrupt (e.g. what is causing it)?

Best regards
David