add mpstat-like command for mac os x

macosx/.gitignore

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+cpu_usage

macosx/Makefile

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+
+
+CC=gcc
+
+
+all:	cpu_usage
+
+cpu_usage:	cpu_usage.c
+	$(CC) -o $@ $<
+
+clean:
+	rm -f cpu_usage

macosx/README.md

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+# Mac OS X Tools
+
+## cpu_usage
+
+Mac OS X lacks, perhaps unsurprisingly, a command line tool to emit
+the sort of data one expects from _mpstat(1)_.  This tool seeks to
+print CPU Usage figures for each core in the format expected by
+_heatmap_.
+

macosx/cpu_usage.c

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+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+#include <mach/mach.h>
+#include <mach/processor_info.h>
+#include <mach/mach_host.h>
+#include <time.h>
+
+typedef struct cpu_load {
+	int cl_system;
+	int cl_user;
+	int cl_nice;
+	int cl_idle;
+} cpu_load_t;
+
+int cpu_count = -1;
+cpu_load_t *cpu_load = NULL;
+
+void
+update_cpu_load()
+{
+	kern_return_t error;
+	natural_t nmpu;
+	processor_info_array_t info;
+	mach_msg_type_number_t cnt;
+	int infosz;
+	int i;
+	int firstrun = 0;
+
+	error = host_processor_info(mach_host_self(), PROCESSOR_CPU_LOAD_INFO,
+	    &nmpu, &info, &cnt);
+	if (error != KERN_SUCCESS) {
+		mach_error("update_cpu_load1", error);
+		exit(1);
+	}
+
+	if (cpu_load == NULL) {
+		cpu_count = nmpu;
+		cpu_load = calloc(nmpu, sizeof (cpu_load_t));
+		firstrun = 1;
+	}
+
+	infosz = cnt / nmpu;
+
+	for (i = 0; i < nmpu; i++) {
+		cpu_load_t newload;
+		newload.cl_system = info[CPU_STATE_SYSTEM + i * infosz];
+		newload.cl_user = info[CPU_STATE_USER + i * infosz];
+		newload.cl_nice = info[CPU_STATE_NICE + i * infosz];
+		newload.cl_idle = info[CPU_STATE_IDLE + i * infosz];
+		if (!firstrun) {
+			int delta_system = newload.cl_system -
+				cpu_load[i].cl_system;
+			int delta_user = newload.cl_user -
+				cpu_load[i].cl_user;
+			int delta_nice = newload.cl_nice -
+				cpu_load[i].cl_nice;
+			int delta_idle = newload.cl_idle -
+				cpu_load[i].cl_idle;
+
+			int used = delta_system + delta_user + delta_nice;
+			int percent = 100 * used / (used + delta_idle);
+
+			fprintf(stdout, "%d ", percent);
+		}
+		memcpy(&cpu_load[i], &newload, sizeof (cpu_load_t));
+	}
+	if (!firstrun)
+		fprintf(stdout, "\n");
+
+	vm_deallocate(mach_task_self(), (vm_address_t)info, cnt);
+}
+
+int
+main(int argc, char **argv)
+{
+	setvbuf(stdout, NULL, _IOLBF, 0);
+
+	for (;;) {
+		update_cpu_load();
+		sleep(1);
+	}
+}