From f0eb7c327acbeb6a077e516a6790dc155bbf9eb4 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Mon, 2 May 2016 23:28:51 +0200
Subject: [PATCH] add benchmark to measure the overhead of common system calls

---
 hermit/usr/benchmarks/Makefile |  10 ++-
 hermit/usr/benchmarks/basic.c  | 128 +++++++++++++++++++++++++++++++++
 2 files changed, 137 insertions(+), 1 deletion(-)
 create mode 100644 hermit/usr/benchmarks/basic.c

diff --git a/hermit/usr/benchmarks/Makefile b/hermit/usr/benchmarks/Makefile
index d7d8590d6..c322054c4 100644
--- a/hermit/usr/benchmarks/Makefile
+++ b/hermit/usr/benchmarks/Makefile
@@ -44,7 +44,7 @@ endif
 
 default: all
 
-all: stream hg netio RCCE_pingping RCCE_pingpong
+all: stream hg netio RCCE_pingping RCCE_pingpong basic
 
 stream.o: stream.c
 	@echo [CC] $@
@@ -58,6 +58,14 @@ stream: stream.o
 	$Q$(ELFEDIT_FOR_TARGET) --output-osabi HermitCore $@
 	$Qchmod a-x $@.sym
 
+basic: basic.o
+	@echo [LD] $@
+	$Q$(CC_FOR_TARGET) $(LDFLAGS_FOR_TARGET) $(CFLAGS_FOR_TARGET) -o $@ $<
+	$Q$(OBJCOPY_FOR_TARGET) $(KEEP_DEBUG) $@ $@.sym
+	$Q$(OBJCOPY_FOR_TARGET) $(STRIP_DEBUG) $@
+	$Q$(ELFEDIT_FOR_TARGET) --output-osabi HermitCore $@
+	$Qchmod a-x $@.sym
+
 RCCE_pingping: RCCE_pingping.o
 	@echo [LD] $@
 	$Q$(CC_FOR_TARGET) $(LDFLAGS_FOR_TARGET) $(CFLAGS_FOR_TARGET) -o $@ $< -lircce
diff --git a/hermit/usr/benchmarks/basic.c b/hermit/usr/benchmarks/basic.c
new file mode 100644
index 000000000..d4f2d9b4e
--- /dev/null
+++ b/hermit/usr/benchmarks/basic.c
@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) 2016, Stefan Lankes, RWTH Aachen University
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *    * Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *    * Neither the name of the University nor the names of its contributors
+ *      may be used to endorse or promote products derived from this
+ *      software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __hermit__
+#define _GNU_SOURCE
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#ifndef __hermit__
+#include <sched.h>
+#include <sys/syscall.h>
+
+static inline long mygetpid(void)
+{
+	return syscall(__NR_getpid);
+}
+
+static inline void reschedule(void)
+{
+	sched_yield();
+}
+#else
+static inline long mygetpid(void)
+{
+	return getpid();
+}
+
+void reschedule(void);
+#endif
+
+#define N		10000
+#define M		(1024)
+#define BUFFSZ		(1ULL*1024ULL*1024ULL)
+
+static char* buff[M];
+
+inline static unsigned long long rdtsc(void)
+{
+	unsigned long lo, hi;
+	asm volatile ("rdtsc" : "=a"(lo), "=d"(hi) :: "memory");
+	return ((unsigned long long) hi << 32ULL | (unsigned long long) lo);
+}
+
+int main(int argc, char** argv)
+{
+	long i, j, ret;
+	unsigned long long start, end;
+	const char str[] = "H";
+	size_t len = strlen(str);
+
+	printf("Determine systems performance\n\n");
+
+	ret = mygetpid();
+	ret = mygetpid();
+	start = rdtsc();
+	for(i=0; i<N; i++)
+		ret = mygetpid();
+	end = rdtsc();
+
+	printf("Average time for getpid: %lld cycles, pid %ld\n", (end - start) / N, ret);
+
+	reschedule();
+	reschedule();
+	start = rdtsc();
+	for(i=0; i<N; i++)
+		reschedule();
+	end = rdtsc();
+
+	printf("Average time for sched_yield: %lld cycles\n", (end - start) / N);
+
+	malloc(1);
+	malloc(1);
+	start = rdtsc();
+	for(i=0; i<M; i++)
+		buff[i] = (char*) malloc(BUFFSZ);
+	end = rdtsc();
+
+	printf("Average time for malloc: %lld cycles\n", (end - start) / M);
+
+	start = rdtsc();
+	for(i=0; i<M; i++)
+		for(j=0; j<BUFFSZ; j+=4096)
+			buff[i][j] = '1';
+	end = rdtsc();
+
+	printf("Average time for the first page access: %lld cycles\n", (end - start) / (M*BUFFSZ/4096));
+
+#if 0
+	write(2, (const void *)str, len);
+	write(2, (const void *)str, len);
+	start = rdtsc();
+	for(i=0; i<N; i++)
+		write(2, (const void *)str, len);
+	end = rdtsc();
+
+	printf("\nAverage time for write: %lld cycles\n", (end - start) / N);
+#endif
+
+	return 0;
+}