How to make Modelsim dump the data immediately?

Hi, guys!
I'm using Modelsim to run a sdf timing simulation. In the testbench, I make several important signals to output the values into some text files using $fdisplay system task function. So I can compare the output file with an "ideal output" file made by Matlab simulation to evaluate whether the design is correct. Because the simulation is rather slow, I want to firstly run the simulation for several microseconds and break it and compare the outputs first, if the output has became wrong, I don't need to keep going and will stop to find the bugs in my design. If the output is correct, I can resume the simulation for longer time.

Now I meet a problem: Modelsim does not output the result of the signal immediately, otherwise, it keep the data in memory. Until the data is "enough" or the simulation is stopped, the simulator will not dump it into the text files. So I found I can't preview the simulation rusult just as I wish, it really bother me. Can anyone tell me how to dump "the data to fdisplay" immediately or whenever I want to? Maybe it need a command or some special code in testbench? I will be very thankful!

u should stop the simulation to see the result,for the access to the text file cann't change from modelsim to u.or u can dump a short text file , but u should close it when u finish dump the data u want.
or u can $display the result on the modelsim window for some result.