crs/msm: optimizations

Signed-off-by: Ignacio Hagopian <jsign.uy@gmail.com>
jsign · Sep 21, 2023 · bf51871 · bf51871
1 parent a828a95
commit bf51871
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Showing 2 changed files with 19 additions and 11 deletions.
diff --git a/src/bench.zig b/src/bench.zig
@@ -8,12 +8,13 @@ const multiproof = @import("multiproof/multiproof.zig");
 const polynomials = @import("polynomial/lagrange_basis.zig");
 const ipa = @import("ipa/ipa.zig");
 const Transcript = @import("ipa/transcript.zig");
+const precomp = @import("crs/msm.zig");
 
 pub fn main() !void {
-    // benchFields();
+    benchFields();
     try benchPedersenHash();
-    // try benchIPAs();
-    // try benchMultiproofs();
+    try benchIPAs();
+    try benchMultiproofs();
 }
 
 fn benchFields() void {
@@ -47,7 +48,7 @@ fn benchFields() void {
 fn benchPedersenHash() !void {
     std.debug.print("Benchmarking Pedersen hashing...\n", .{});
     const xcrs = crs.CRS.init();
-    const N = 200;
+    const N = 500;
 
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer {
@@ -56,6 +57,9 @@ fn benchPedersenHash() !void {
     }
     var allocator = gpa.allocator();
 
+    var precomp_msm = try precomp.PrecompMSM.init(allocator, &xcrs.Gs, 8);
+    defer precomp_msm.deinit();
+
     var vec_len: usize = 1;
     while (vec_len <= 256) : (vec_len <<= 1) {
         std.debug.print("\twith {} elements... ", .{vec_len});
@@ -75,7 +79,13 @@ fn benchPedersenHash() !void {
         for (0..N) |i| {
             _ = xcrs.commit(vecs[i]);
         }
-        std.debug.print("takes {}µs\n", .{@divTrunc((std.time.microTimestamp() - start), (N))});
+        std.debug.print(" naive takes {}µs", .{@divTrunc((std.time.microTimestamp() - start), (N))});
+
+        start = std.time.microTimestamp();
+        for (0..N) |i| {
+            _ = try precomp_msm.msm(vecs[i][0..vec_len]);
+        }
+        std.debug.print(", optimized takes {}µs\n", .{@divTrunc((std.time.microTimestamp() - start), (N))});
     }
 }
 

diff --git a/src/crs/msm.zig b/src/crs/msm.zig
@@ -4,7 +4,7 @@ const banderwagon = @import("../banderwagon/banderwagon.zig");
 const Element = banderwagon.Element;
 const Fr = banderwagon.Fr;
 
-const PrecompMSM = struct {
+pub const PrecompMSM = struct {
     allocator: Allocator,
     b: usize,
     basis_len: usize,
@@ -47,7 +47,9 @@ const PrecompMSM = struct {
         const num_windows = self.basis_len / self.b;
         var accum = Element.identity();
         for (0..253) |k| {
-            accum.double(accum);
+            if (k > 0) {
+                accum.double(accum);
+            }
             for (0..num_windows) |w| {
                 if (w * self.b < scalars.len) {
                     const window_scalars = scalars[w * self.b ..];
@@ -103,12 +105,8 @@ test "correctness" {
             }
             full_scalars[i] = Fr.zero();
         }
-        std.debug.print("For {} ...", .{msm_length});
         const exp = CRS.commit(full_scalars);
-        std.debug.print("ok", .{});
-
         const got = try precomp.msm(msm_scalars);
-        std.debug.print(" ok\n", .{});
 
         try std.testing.expect(Element.equal(exp, got));
     }