Add lots of repetitions to small host operations

UBC-ECE-Sasha · Aug 20, 2020 · a0b0a4b · a0b0a4b
1 parent d217625
commit a0b0a4b
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Showing 2 changed files with 51 additions and 41 deletions.
diff --git a/host/aesni_crypto.c b/host/aesni_crypto.c
@@ -17,47 +17,51 @@ int aesni_AES_ecb(void *in, void *out, unsigned long length,
   struct timespec start, end;
   clock_gettime(CLOCK_MONOTONIC_RAW, &start);
 
-  // OpenSSL only accepts an integer length, so we reject lengths any longer
-  // than that
-  if (length > INT_MAX) {
-    return EINVAL;
-  }
+  int nr_repetitions = (GIGABYTE(1) + length - 1) / length;
 
-  if (operation == OP_ENCRYPT) {
-    operation = 1;
-  } else if (operation == OP_DECRYPT) {
-    operation = 0;
-  } else {
-    return EINVAL;
-  }
+  for (int i = 0; i < nr_repetitions; i++) {
+    // OpenSSL only accepts an integer length, so we reject lengths any longer
+    // than that
+    if (length > INT_MAX) {
+      return EINVAL;
+    }
 
-  EVP_CIPHER_CTX *ctx;
+    if (operation == OP_ENCRYPT) {
+      operation = 1;
+    } else if (operation == OP_DECRYPT) {
+      operation = 0;
+    } else {
+      return EINVAL;
+    }
 
-  if (!(ctx = EVP_CIPHER_CTX_new())) {
-    handleErrors();
-  }
+    EVP_CIPHER_CTX *ctx;
 
-  if (1 != EVP_CipherInit_ex(ctx, EVP_aes_128_ecb(), NULL, key_ptr, NULL,
-                             operation)) {
-    handleErrors();
-  }
+    if (!(ctx = EVP_CIPHER_CTX_new())) {
+      handleErrors();
+    }
 
-  int outl;
+    if (1 != EVP_CipherInit_ex(ctx, EVP_aes_128_ecb(), NULL, key_ptr, NULL,
+                               operation)) {
+      handleErrors();
+    }
 
-  if (1 != EVP_CipherUpdate(ctx, out, &outl, in, length)) {
-    handleErrors();
-  }
+    int outl;
+
+    if (1 != EVP_CipherUpdate(ctx, out, &outl, in, length)) {
+      handleErrors();
+    }
+
+    if (length != (unsigned int)outl) {
+      ERROR("Error: OpenSSL did not encrypt all data\n");
+      EVP_CIPHER_CTX_free(ctx);
+      return -1;
+    }
 
-  if (length != (unsigned int)outl) {
-    ERROR("Error: OpenSSL did not encrypt all data\n");
     EVP_CIPHER_CTX_free(ctx);
-    return -1;
   }
 
-  EVP_CIPHER_CTX_free(ctx);
-
   clock_gettime(CLOCK_MONOTONIC_RAW, &end);
-  double execution_time = TIME_DIFFERENCE(start, end);
+  double execution_time = TIME_DIFFERENCE(start, end) / nr_repetitions;
 
   // TODO: add a cycle count
   // Operation, Data size, Execution time

diff --git a/host/host_crypto.c b/host/host_crypto.c
@@ -13,20 +13,26 @@ int host_AES_ecb(void *in, void *out, unsigned long length, const void *key_ptr,
 
   clock_gettime(CLOCK_MONOTONIC_RAW, &start);
 
-  switch (operation) {
-  case OP_ENCRYPT:
-    host_AES_ecb_encrypt(in, out, length, key_ptr);
-    break;
-  case OP_DECRYPT:
-    host_AES_ecb_decrypt(in, out, length, key_ptr);
-    break;
-  default:
-    return 1;
-  }
+  int nr_repetitions = (MEGABYTE(256) + length - 1) /
+                       length; // This aims to have each execution take at least
+                               // 1s, with more repetitions for smaller numbers
+                               // that tend to have less precision
 
+  for (int i = 0; i < nr_repetitions; i++) {
+    switch (operation) {
+    case OP_ENCRYPT:
+      host_AES_ecb_encrypt(in, out, length, key_ptr);
+      break;
+    case OP_DECRYPT:
+      host_AES_ecb_decrypt(in, out, length, key_ptr);
+      break;
+    default:
+      return 1;
+    }
+  }
   clock_gettime(CLOCK_MONOTONIC_RAW, &end);
 
-  double execution_time = TIME_DIFFERENCE(start, end);
+  double execution_time = TIME_DIFFERENCE(start, end) / nr_repetitions;
 
   // TODO: add a cycle count
   // Operation, Data size, Execution time