Added a benchmark for counting context-switches per second.

bench/Makefile

@@ -5,6 +5,7 @@ include ../crosscompilemakefile.mak
 INITRDDIR:=../initrd
 LOCALBINARIES:=\
 benchsyscall \
+benchctxswitch \
 
 BINARIES:=$(addprefix $(INITRDDIR)/,$(LOCALBINARIES))
 

bench/benchctxswitch.cpp

+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+
+int main(int argc, char* argv[])
+{
+	pid_t slavepid = fork();
+	if ( slavepid < 0 ) { perror("fork"); return 1; }
+	if ( slavepid == 0 ) { while ( true ) { usleep(0); } exit(0); }
+
+	uintmax_t start;
+	if ( uptime(&start) ) { perror("uptime"); return 1; }
+	uintmax_t end = start + 1ULL * 1000ULL; // 1 second
+	size_t count = 0;
+	uintmax_t now;
+	while ( !uptime(&now) && now < end ) { usleep(0); count += 2; /* back and forth */ }
+	printf("Made %zu context switches in 1 second\n", count);
+
+	kill(slavepid, SIGKILL);
+
+	return 0;
+}