junrushao1994 commented on a change in pull request #8817:
URL: https://github.com/apache/tvm/pull/8817#discussion_r694394696



##########
File path: src/tir/schedule/concrete_schedule.cc
##########
@@ -208,6 +211,25 @@ Schedule ConcreteScheduleNode::Copy() const {
   }
 
 /******** Schedule: Schedule: Sampling ********/
+
+void ConcreteScheduleNode::Seed(support::LinearCongruentialEngine::TRandState 
seed) {
+  support::LinearCongruentialEngine(&rand_state_).Seed(seed == -1 ? 
std::random_device()() : seed);
+}
+support::LinearCongruentialEngine::TRandState ConcreteScheduleNode::ForkSeed() 
{
+  // In order for reproducibility, we computer the new seed using RNG's random 
state and a different
+  // set of parameters. Note that both 32767 and 1999999973 are prime numbers.
+  return (support::LinearCongruentialEngine(&rand_state_)() * 32767) % 
1999999973;
+}

Review comment:
       Here is a quick example, supposing we have 64 threads and repeated for 
10k times: 
https://gist.github.com/junrushao1994/ea986add81b01b89fd99a5a7d41d087a, and the 
result is that there is no repetition.
   
   I actually agree with Tristan's theory in general, but in our particular 
case it is not a big problem. To make sure it works generally, we can switch 
PRNGs by replacing support::LCG with other random number generators :-)
   
   




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