perf: get_cycles don't need emit events (#697)

core/src/runtime/mod.rs

@@ -912,6 +912,11 @@ impl Runtime {
         while !self.execute() {}
     }
 
+    pub fn dry_run(&mut self) {
+        self.emit_events = false;
+        while !self.execute() {}
+    }
+
     /// Executes up to `self.shard_batch_size` cycles of the program, returning whether the program has finished.
     fn execute(&mut self) -> bool {
         // If it's the first cycle, initialize the program.

prover/src/utils.rs

@@ -30,7 +30,7 @@ pub fn get_cycles(elf: &[u8], stdin: &SP1Stdin) -> u64 {
     let program = Program::from(elf);
     let mut runtime = Runtime::new(program);
     runtime.write_vecs(&stdin.buffer);
-    runtime.run();
+    runtime.dry_run();
     runtime.state.global_clk
 }