Resolution:
If the log level is set to DEBUG = 0 (tibco.clientVar.ASG/Logging/MinLogLevel=0) in the asg.properties, then the engine logs in the caching core log file the following entry

2014 May 14 13:21:09:013 GMT -7 asg-caching-core Info [$default.be.mt$.Thread.4] - [user] [core-class] DEBUG: RF  ScheduleThrottleUpdate fired, time n
ow->  Wed,2014-05-14 13:21:09.013 -0700
2014 May 14 13:21:11:002 GMT -7 asg-caching-core Info [$default.be.mt$.Thread.3] - [user] [core-class] DEBUG: RF  ScheduleAcceptGrant fired, time now-
>  Wed,2014-05-14 13:21:11.002 -0700
2014 May 14 13:21:11:004 GMT -7 asg-caching-core Info [$default.be.mt$.Thread.3] - [user] [core-class] WARN: ApplyGrant rule: no updates since last in
terval. Checking time of day modifiers.

If the log level is set to 1 or 2 (INFO or WARN) then only the last line is logged:

2014 May 14 13:21:11:004 GMT -7 asg-caching-core Info [$default.be.mt$.Thread.3] - [user] [core-class] WARN: ApplyGrant rule: no updates since last in
terval. Checking time of day modifiers.

These log entries are logged for the time interval specified as per the property updateInterval in the asg.properties file, by default its set as 10 sec
tibco.clientVar.ASG/Throttle/UpdateIntervalSec=10

In any APIX engine set in INFO or WARN the entry would repeat every 10 seconds by default. To avoid the entry, switch logging to Error or No logging (3/4). One may also increase the interval to have fewer entries in log file, but care must be taken as the value is used for throttle calculation. Refer to: https://docs.tibco.com/pub/api-exchange-gateway/2.1.0/doc/html/TIB_api-exchange-gateway_users_guide/wwhelp/wwhimpl/common/html/wwhelp.htm#href=GatewayManagement.16.4.htm&single=true

GTM (Global Throttle Manager) log entries in Core log file.