Roman Posted March 25, 2011 Report Share Posted March 25, 2011 Hi , I have a question regarding set_drain_time(xx,xx). As i saw in the UVM spec, "The drain time is the amount of time to wait once all objections have been dropped before calling the all_dropped callback and propagating the objection to the parent" why we need set a drain time for the environment ? how to make sure how much time to set for drain_time? Quote Link to comment Share on other sites More sharing options...
uwes Posted March 25, 2011 Report Share Posted March 25, 2011 Hi ,I have a question regarding set_drain_time(xx,xx). As i saw in the UVM spec, "The drain time is the amount of time to wait once all objections have been dropped before calling the all_dropped callback and propagating the objection to the parent" why we need set a drain time for the environment ? how to make sure how much time to set for drain_time? hi, the drain time is a 'grace' period after the objections have been dropped until the effect becomes visiible. the most prominent case is uvm_test_done. without a drain time your simulator would be stopped right with dropping the last objection however in most cases you still want to spend some simulation cycles to shitdown your whole system gracefully (no transfers going on anymore, no assertions running, ...) the length of the drain time depends upon your device. it should be slightly larger then the maximum time your device needs to complete the remaining activities Quote Link to comment Share on other sites More sharing options...
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