In reply to Reuben:
Yes, my mistake.
Actually the FIFOs are in the uvm_in_order_comparator, and uvm_in_order_comparator is extended from uvm_component. do_flush is defined as
2007 function void uvm_component::do_flush();
2008 foreach( m_children[s] )
2009 m_children[s].do_flush();
2010 flush();
2011 endfunc tion
Since the fifos are children of uvm_in_order_comparator, their do_flush methods should have been called, which would eventually call the uvm_tlm_fifo::flush() method. So I don’t understand why you say your FIFOS are not getting flushed.