Add cpustat (C implementation) to get rid of iostat/sysctl/etc

cpu

@@ -75,5 +75,7 @@ if [ "$1" = "config" ]; then
 	exit 0
 fi
 
-iostat -c2 -w0.1 -n0 | tail -1 | awk '{ print "user.value " $3 "\nnice.value " $4 "\nsystem.value " $5 "\ninterrupt.value " $6 "\nidle.value " $7 }'
+#iostat -c2 -w0.1 -n0 | tail -1 | awk '{ print "user.value " $3 "\nnice.value " $4 "\nsystem.value " $5 "\ninterrupt.value " $6 "\nidle.value " $7 }'
+# It expects to find our cpustat binary in /usr/local/bin
+/usr/local/bin/cpustat
 

cpustat/Makefile

@@ -0,0 +1,24 @@
+CC?=
+PREFIX?=/usr/local
+CPPFLAGS=-I$(PREFIX)/include
+CFLAGS=-Wall -Wextra -g -O2 -pipe -funroll-loops -ffast-math -fno-strict-aliasing
+CFLAGS+=$(CPPFLAGS)
+LDFLAGS=-L$(PREFIX)/lib
+LDLIBS=-lm
+RM?=rm -f
+
+CPUSTAT = cpustat
+OBJ = cpustat.o
+
+all: $(CPUSTAT)
+
+$(CPUSTAT): $(OBJ)
+	$(CC) $(LDFLAGS) $(OBJ) $(LDLIBS) -o $?
+
+install: all
+	install -s -C $(CPUSTAT) $(PREFIX)/bin
+
+clean:
+	$(RM) *.o *.a a.out core temp.* $(PROGS)
+	$(RM) -r *.dSYM
+

cpustat/cpustat.c

@@ -0,0 +1,72 @@
+/*-
+ * Copyright (c) 2018, Babak Farrokhi
+ * 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.
+ *
+ * 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 COPYRIGHT HOLDER 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.
+*/
+
+#include <devstat.h>
+#include <err.h>
+#include <kvm.h>
+#include <math.h>
+#include <stdio.h>
+#include <strings.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+
+static struct statinfo cur;
+kvm_t *kd = NULL;
+
+static int readvar(kvm_t *kd, const char *name, int nlid, void *ptr,
+                   size_t len) {
+    size_t nlen = len;
+
+    if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
+        warn("sysctl(%s...) failed", name);
+        return (1);
+    }
+    if (nlen != len) {
+        warnx("sysctl(%s...): expected %lu, got %lu", name, (unsigned long)len,
+              (unsigned long)nlen);
+        return (1);
+    }
+    return (0);
+}
+
+static void cpustats(void) {
+    int state;
+    double cptime = 0.0;
+    char *names[] = {"user", "nice", "system", "interrupt", "idle"};
+
+    readvar(kd, "kern.cp_time", 0, &cur.cp_time, sizeof(cur.cp_time));
+
+    for (state = 0; state < CPUSTATES; ++state)
+        cptime += cur.cp_time[state];
+    for (state = 0; state < CPUSTATES; ++state)
+        printf("%s.value %.0f\n", names[state],
+               rint(100. * cur.cp_time[state] / (cptime ? cptime : 1)));
+}
+
+int main(void) 
+{ 
+    cpustats(); 
+}