Cisco 2921 Router Usage High REVT Process

[astreetman]

Before I begin, let me say that I've scoured both the Cisco forums as well as the internet at large (Google is my friend)... I cannot for the life of me figure out what this process is, or why it is consuming half of the CPU on average on two of our 2921 routers.

Can someone shed some light on what this REVT background process is and if this is normal? The routers both began experiencing this issue about a week and half ago.

CPU utilization for five seconds: 54%/0%; one minute: 56%; five minutes: 56%

PID Runtime(ms)     Invoked      uSecs   5Sec   1Min   5Min TTY Process

  50   826761040   154465780       5352 49.43% 47.78% 45.38%   0 REVT background

144      826756     4902358        168  2.95%  4.93%  6.90%   0 IP Input

342       15684   260682271          0  0.47%  0.55%  0.55%   0 IP SLAs XOS Even

271       43288      722396         59  0.31%  0.43%  0.50%   0 Crypto PAS Proc

108        4712   132672198          0  0.15%  0.15%  0.15%   0 Ethernet Msec Ti

  91        8656     4190697          2  0.15%  0.16%  0.16%   0 Netclock Backgro

340         540     1058838          0  0.07%  0.00%  0.00%   0 CFT Timer Proces

152        1468        3582        409  0.07%  0.00%  0.00% 389 SSH Process

103       26268     2095089         12  0.07%  0.03%  0.02%   0 BPSM stat Proces

345      680332      436665       1558  0.07%  0.00%  0.08%   0 SNMP ENGINE

140        1820    33239725          0  0.07%  0.03%  0.02%   0 IPAM Manager

[Miroslav Sturmankin]

Hello,

I have simmilar problem with 3925 and ISM-VPN module. Check the bug CSCtz51773 and see if it helps:

http://www.cisco.com/en/US/docs/ios/15_2m_and_t/release/notes/152-2TCAVS.html

CSCtz51773 
Symptoms: High CPU seen on routers equipped with an ISM-VPN module. The output of show process cpu shows that the process "REVT Background" is using around 70% of the CPU cycles. 
The ISM-VPN module is not visible in show diag, and the output of show crypto engine configuration indicates that the module status is DEAD. 
Conditions: The symptom is observed with an ISM VPN with a few IPSec tunnels. This can take between a day and a week. 
Workaround 1: Reload the router. 
Workaround 2: For a longer-run workaround and if the traffic volume is not too high, switch to the onboard crypto hardware using the configuration no crypto engine slot 0. 

The bug should be fixed in 15.2(2)T2.

[Bedevere Curry]

Nice. Very useful. I just ran into this issue

[Miroslav Sturmankin]

The bug that was supposed to be fixed in 15.2(2)T2 was not fixed thoroughly and we had still the issues in our setup (with certificates > 4096B). Case was reopened in 2013 under CSCue01721

From the first words the fix was supposed to be in 15.3(3)T, which is not available, yet. But I got a info from TAC on my case that the available IOS with the fix is 15.2(4)M4 (was released in June). So far we are running without problems over six weeks on 3925+ISM-VPN module. According to CSC, it should be fixed also in another major release 15.3(2)T1 that just came out in August.