From 6a0206897c83e1f3e4539d6a6c77149167f49626 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Sun, 5 Sep 2021 12:17:38 +0200
Subject: stupidgcm: add BenchmarkCCall

gocryptfs/internal/stupidgcm$ go test -bench .
goos: linux
goarch: amd64
pkg: github.com/rfjakob/gocryptfs/v2/internal/stupidgcm
cpu: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz
BenchmarkCCall-4   	15864030	        78.60 ns/op
PASS
ok  	github.com/rfjakob/gocryptfs/v2/internal/stupidgcm	1.898s
---
 internal/stupidgcm/common_test.go | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'internal/stupidgcm/common_test.go')

diff --git a/internal/stupidgcm/common_test.go b/internal/stupidgcm/common_test.go
index a8080ca..589d974 100644
--- a/internal/stupidgcm/common_test.go
+++ b/internal/stupidgcm/common_test.go
@@ -208,3 +208,24 @@ func randBytes(n int) []byte {
 	}
 	return b
 }
+
+/*
+BenchmarkCCall benchmarks the overhead of calling from Go into C.
+Looks like things improved a bit compared to
+https://www.cockroachlabs.com/blog/the-cost-and-complexity-of-cgo/
+where they measured 171ns/op:
+
+$ go test -bench .
+goos: linux
+goarch: amd64
+pkg: github.com/rfjakob/gocryptfs/v2/internal/stupidgcm
+cpu: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz
+BenchmarkCCall-4   	13989364	        76.72 ns/op
+PASS
+ok  	github.com/rfjakob/gocryptfs/v2/internal/stupidgcm	1.735s
+*/
+func BenchmarkCCall(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		noopCFunction()
+	}
+}
-- 
cgit v1.2.3