bench: Add support for measuring CPU cycles

This adds cycle min/max/avg to the statistics.

Supported on x86 and x86_64 (natively through rdtsc), as well as Linux
(perf syscall).

1 files changed, 37 insertions, 0 deletions

diff --git a/src/bench/perf.h b/src/bench/perf.h
new file mode 100644
index 0000000000..681bd0c8a2
--- /dev/null
+++ b/src/bench/perf.h
@@ -0,0 +1,37 @@
+// Copyright (c) 2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+/** Functions for measurement of CPU cycles */
+#ifndef H_PERF
+#define H_PERF
+
+#include <stdint.h>
+
+#if defined(__i386__)
+
+static inline uint64_t perf_cpucycles(void)
+{
+    uint64_t x;
+    __asm__ volatile (".byte 0x0f, 0x31" : "=A" (x));
+    return x;
+}
+
+#elif defined(__x86_64__)
+
+static inline uint64_t perf_cpucycles(void)
+{
+    uint32_t hi, lo;
+    __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
+    return ((uint64_t)lo)|(((uint64_t)hi)<<32);
+}
+#else
+
+uint64_t perf_cpucycles(void);
+
+#endif
+
+void perf_init(void);
+void perf_fini(void);
+
+#endif // H_PERF