feat(zkvms_guest_io): Output proof size

In each zkVM we'll write the size to /tmp/proof_size and then guest_io
will read that value and place it inside our metrics output. This is not
the most elegant, and in certain zkVMs the file output is a part of the
benchmark timing, but it will have to do.

1 files changed, 7 insertions, 1 deletions

diff --git a/zkvms/sp1/host/src/main.rs b/zkvms/sp1/host/src/main.rs
index 6d19000..a395247 100644
--- a/zkvms/sp1/host/src/main.rs
+++ b/zkvms/sp1/host/src/main.rs
@@ -2,6 +2,7 @@ use sp1_sdk::{EnvProver, ProverClient, SP1ProofWithPublicValues, SP1Stdin, SP1Ve
 use zkvms_host_io::{
     benchmarkable, foreach_input_field, read_args, Input,
     RunType::{Execute, Prove, Verify},
+    output_proof_size,
 };
 
 /// The ELF (executable and linkable format) file for the Succinct RISC-V zkVM.
@@ -40,13 +41,18 @@ fn main() {
             println!("Number of cycles: {}", report.total_instruction_count());
         },
         Prove => benchmarkable! {
-            let _ = prove(&client, stdin.clone());
+            let (proof, _) = prove(&client, stdin.clone());
+
+            output_proof_size(&proof);
+
             println!("Successfully generated proof!");
         },
         Verify => {
             let (proof, vk) = prove(&client, stdin.clone());
             println!("Successfully generated proof!");
 
+            output_proof_size(&proof);
+
             benchmarkable! {
                 client.verify(&proof, &vk).expect("failed to verify proof");
                 println!("Successfully verified proof!");