mbedtls: add SHA performance test

Results with this revision:

SHA256 rate 2.599MB/sec Debug 240MHz SW
SHA256 rate 1.147MB/sec Release 80MHz SW
SHA256 rate 3.469MB/sec Release 240MHz SW
SHA256 rate 2.687MB/sec Release 240MHz SW + PSRAM workaround

SHA256 rate 9.433MB/sec Debug 240MHz HW rev1
SHA256 rate 3.727MB/sec Release 80MHz HW rev1
SHA256 rate 10.961MB/sec Release 240MHz HW rev1
SHA256 rate 9.966MB/sec Release 240MHz HW rev1 + PRAM workaround

SHA256 rate 10.974MB/sec Debug 240MHz HW rev3
SHA256 rate 4.362MB/sec Release 80MHz HW rev3
SHA256 rate 13.207MB/sec Release 240MHz HW rev3

Debug = Og, assertions enabled
Release = O2, assertions disabled

components/idf_test/include/idf_performance.h

@@ -30,4 +30,6 @@
 // floating point instructions per divide and per sqrt (configured for worst-case with PSRAM workaround)
 #define IDF_PERFORMANCE_MAX_ESP32_CYCLES_PER_DIV 70
 #define IDF_PERFORMANCE_MAX_ESP32_CYCLES_PER_SQRT 140
+// SHA256 hardware throughput at 240MHz, threshold set lower than worst case
+#define IDF_PERFORMANCE_MIN_SHA256_THROUGHPUT_MBSEC                             9.0
 

components/mbedtls/test/CMakeLists.txt

@@ -1,6 +1,6 @@
 idf_component_register(SRC_DIRS "."
                     INCLUDE_DIRS "."
-                    REQUIRES unity test_utils mbedtls)
+                    REQUIRES unity test_utils mbedtls libsodium)
 
 idf_component_get_property(mbedtls mbedtls COMPONENT_LIB)
 target_compile_definitions(${mbedtls} INTERFACE "-DMBEDTLS_DEPRECATED_WARNING")

components/mbedtls/test/test_sha_perf.c

@@ -0,0 +1,58 @@
+/* mbedTLS SHA performance test
+*/
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include "mbedtls/sha256.h"
+#include "unity.h"
+#include "sdkconfig.h"
+#include "esp_timer.h"
+#include "esp_heap_caps.h"
+#include "test_utils.h"
+#include "sodium/utils.h"
+
+TEST_CASE_ESP32("mbedtls SHA performance", "[aes]")
+{
+    const unsigned CALLS = 256;
+    const unsigned CALL_SZ = 16*1024;
+    mbedtls_sha256_context sha256_ctx;
+    int64_t start, end;
+    unsigned char sha256[32];
+
+    // allocate internal memory
+    uint8_t *buf = heap_caps_malloc(CALL_SZ, MALLOC_CAP_8BIT|MALLOC_CAP_INTERNAL);
+    TEST_ASSERT_NOT_NULL(buf);
+    memset(buf, 0x55, CALL_SZ);
+
+    mbedtls_sha256_init(&sha256_ctx);
+    start = esp_timer_get_time();
+    TEST_ASSERT_EQUAL(0, mbedtls_sha256_starts_ret(&sha256_ctx, false));
+    for (int c = 0; c < CALLS; c++) {
+        TEST_ASSERT_EQUAL(0, mbedtls_sha256_update_ret(&sha256_ctx, buf, CALL_SZ));
+    }
+    TEST_ASSERT_EQUAL(0, mbedtls_sha256_finish_ret(&sha256_ctx, sha256));
+    end = esp_timer_get_time();
+
+    free(buf);
+    mbedtls_sha256_free(&sha256_ctx);
+
+    /* Check the result. Reference value can be calculated using:    
+     * dd if=/dev/zero bs=$((16*1024)) count=256 | tr '\000' '\125' | sha256sum 
+     */
+    const char* expected_hash = "c88df2638fb9699abaad05780fa5e0fdb6058f477069040eac8bed3231286275";
+    char hash_str[sizeof(sha256) * 2 + 1];
+    sodium_bin2hex(hash_str, sizeof(hash_str), sha256, sizeof(sha256));
+
+    TEST_ASSERT_EQUAL_STRING(expected_hash, hash_str);
+
+    float usecs = end - start;
+    // bytes/usec = MB/sec
+    float mb_sec = (CALL_SZ * CALLS) / usecs;
+    printf("SHA256 rate %.3fMB/sec\n", mb_sec);
+#ifdef CONFIG_MBEDTLS_HARDWARE
+    // Don't put a hard limit on software SHA performance
+    TEST_PERFORMANCE_GREATER_THAN(SHA256_THROUGHPUT_MBSEC, "%.3fMB/sec", mb_sec);
+#endif
+}
+
+