I discovered that 2 of my RB2011 had suddenly an increase on CPU utilization. On one box the profiler was showing 25% CPU was used by spi. I thought it’s stateful packet inspection. I was woundering why this can happen as on these boxes not firewall/nat/connection-tracking is configured. At http://forum.mikrotik.com/t/what-is-tools-profile-spi-usage/70821/1 it’s mentioned that SPI is the LCD on these routers. I know that SPI can be Serial Peripheral Interface and that might be the interface which is used to connect the LCD. I disabled and re-enabled the LCD and the CPU usage was almost gone.
It would be nice if someone from Mikrotik can confirm that spi stands for “Serial Peripheral Interface” and therefor is related to the LCD. It would be even nicer if Mikrotik can complete http://wiki.mikrotik.com/wiki/Manual:Tools/Profiler#Classifiers
I’m wondering why does it suddenly takes so many cpu cycles? And even more confusing is why does it happen on 2 devices at the same time?