high cpu usage for fortisOS 5.4.4

[kinmun]

i am getting very high cpu usage ranging from 30% onwards

we have zabbix monitoring turn on for high cpu usage as well. 

Trigger: Average Usage over 5sec per Processor#3 exceeded 80% Trigger URL:

 Item values:

 1. Average Usage over 5sec per Processor#3 (FortigateTIER2:fgProcessorUsage5sec.["3"]):

90 %

what could be the cause of high httpsd

2_FW01 # get system performance status CPU states: 52% user 5% system 0% nice 43% idle 0% iowait 0% irq 0% softirq CPU0 states: 96% user 3% system 0% nice 1% idle 0% iowait 0% irq 0% softirq CPU1 states: 4% user 2% system 0% nice 94% idle 0% iowait 0% irq 0% softirq CPU2 states: 90% user 7% system 0% nice 2% idle 0% iowait 0% irq 1% softirq CPU3 states: 16% user 10% system 0% nice 74% idle 0% iowait 0% irq 0% softirq Memory states: 59% used Average network usage: 40396 / 41416 kbps in 1 minute, 46332 / 47280 kbps in 10 minutes, 43902 / 45020 kbps in 30 minutes Average sessions: 8331 sessions in 1 minute, 9104 sessions in 10 minutes, 9133 s essions in 30 minutes Average session setup rate: 104 sessions per second in last 1 minute, 84 session s per second in last 10 minutes, 86 sessions per second in last 30 minutes Virus caught: 100 total in 1 minute IPS attacks blocked: 0 total in 1 minute Uptime: 22 days, 16 hours, 52 minutes