Saturday, April 2, 2011

Channel record & playback in VMM !!!

Channel record and playback is useful feature which can be used to reproduce an issue hit at top level environment in a different block level environment. As you know the randomization changes with the change in system Verilog files for the same seed, the same scenario cannot be reproduced with the same seed in a different environment due to the change in the system Verilog files. We need to spend time running random regression with different seeds at block level to reproduce the issue that happened in the top level with a particular sequence. The alternative way to reproduce the issue at block level is to record the transaction at top level which is done using channel record. Then playback the transaction through channel playback from the block level to reproduce the issue.

// Record transaction in top level

gen.out_chan.record("Record_transaction");

// Play back at Block level

gen.out_chan.playback(status,"Record_transaction",tr);

If (!status)

`vmm_error(log,”play back failed \n”);