Jonas,
Thanks for taking the time to post this. I look forward to reading over the release notes.
I see this on my srx300 @ idle as well, high cpu usage that is. We were considering deploying these for a new businsess class product and this has made up hesitant. I have a 220 running version 12 with a similar config and it only using about 3% cpu at idle.
Jarrod@FW1> show version
Hostname: FW1
Model: srx300
Junos: 15.1X49-D60.7
JUNOS Software Release [15.1X49-D60.7]
Jarrod@FW1> show chassis routing-engine
Routing Engine status:
Temperature 50 degrees C / 122 degrees F
CPU temperature 65 degrees C / 149 degrees F
Total memory 4096 MB Max 2540 MB used ( 62 percent)
Control plane memory 2624 MB Max 2152 MB used ( 82 percent)
Data plane memory 1472 MB Max 368 MB used ( 25 percent)
5 sec CPU utilization:
User 57 percent
Background 0 percent
Kernel 3 percent
Interrupt 0 percent
Idle 40 percent
Model RE-SRX300
Serial ID CV2116AF0542
Start time 2016-12-19 19:42:53 UTC
Uptime 2 hours, 34 minutes, 31 seconds
Last reboot reason 0x200:normal shutdown
Load averages: 1 minute 5 minute 15 minute
0.68 0.58 0.57
Jarrod@FW1> show chassis forwarding
FWDD status:
State Online
Microkernel CPU utilization 59 percent
Real-time threads CPU utilization 0 percent
Heap utilization 25 percent
Buffer utilization 1 percent
Uptime: 2 hours, 37 minutes, 2 seconds