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authorJakob Unterwurzacher2021-09-07 12:34:47 +0200
committerJakob Unterwurzacher2021-09-07 18:14:05 +0200
commitf89b14ee3dfa944e275961bf588d0e49500579c4 (patch)
tree030ac167f35b07b3779ad8d79b77a9e29174099a
parent6a0206897c83e1f3e4539d6a6c77149167f49626 (diff)
stupidgcm: cache C.EVP_chacha20_poly1305()
2% performance improvement, almost for free. gocryptfs/internal/speed$ benchstat old new name old time/op new time/op delta StupidXchacha-4 5.82µs ± 0% 5.68µs ± 0% -2.37% (p=0.008 n=5+5) name old speed new speed delta StupidXchacha-4 704MB/s ± 0% 721MB/s ± 0% +2.43% (p=0.008 n=5+5)
-rw-r--r--internal/stupidgcm/chacha.go16
1 files changed, 15 insertions, 1 deletions
diff --git a/internal/stupidgcm/chacha.go b/internal/stupidgcm/chacha.go
index 2e6e6e6..c90d721 100644
--- a/internal/stupidgcm/chacha.go
+++ b/internal/stupidgcm/chacha.go
@@ -21,6 +21,20 @@ type stupidChacha20poly1305 struct {
// Verify that we satisfy the cipher.AEAD interface
var _ cipher.AEAD = &stupidChacha20poly1305{}
+// _EVP_chacha20_poly1305 caches C.EVP_chacha20_poly1305() to avoid the Cgo call
+// overhead for each instantiation of NewChacha20poly1305.
+var _EVP_chacha20_poly1305 *C.EVP_CIPHER
+
+func init() {
+ _EVP_chacha20_poly1305 = C.EVP_chacha20_poly1305()
+}
+
+// NewChacha20poly1305 returns a new instance of the OpenSSL ChaCha20-Poly1305 AEAD
+// cipher ( https://www.openssl.org/docs/man1.1.1/man3/EVP_chacha20_poly1305.html ).
+//
+// gocryptfs only uses ChaCha20-Poly1305 as a building block for OpenSSL
+// XChaCha20-Poly1305. This function is hot because it gets called once for each
+// block by XChaCha20-Poly1305.
func NewChacha20poly1305(key []byte) *stupidChacha20poly1305 {
if len(key) != chacha20poly1305.KeySize {
log.Panicf("Only %d-byte keys are supported, you passed %d bytes", chacha20poly1305.KeySize, len(key))
@@ -28,7 +42,7 @@ func NewChacha20poly1305(key []byte) *stupidChacha20poly1305 {
return &stupidChacha20poly1305{
stupidAEADCommon{
key: append([]byte{}, key...), // private copy
- openSSLEVPCipher: C.EVP_chacha20_poly1305(),
+ openSSLEVPCipher: _EVP_chacha20_poly1305,
nonceSize: chacha20poly1305.NonceSize,
},
}