From fd0f349bffdf61fda8a8085b435ec40d9ddfba33 Mon Sep 17 00:00:00 2001
From: Venkatesh Pallipadi <venki@google.com>
Date: Wed, 1 Feb 2012 17:02:59 -0800
Subject: [PATCH 3/5] test: ipicost test routine

Silly test to measure ipicost.
$ taskset 0x1 cat /proc/ipicost; dmesg | tail -$(($(grep processor /proc/cpuinfo | wc -l)*2))

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
---
 fs/proc/Makefile  |    2 +-
 fs/proc/ipicost.c |  107 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 108 insertions(+), 1 deletions(-)
 create mode 100644 fs/proc/ipicost.c

diff --git a/fs/proc/Makefile b/fs/proc/Makefile
index c1c7293..4407c6f 100644
--- a/fs/proc/Makefile
+++ b/fs/proc/Makefile
@@ -8,7 +8,7 @@ proc-y			:= nommu.o task_nommu.o
 proc-$(CONFIG_MMU)	:= mmu.o task_mmu.o
 
 proc-y       += inode.o root.o base.o generic.o array.o \
-		proc_tty.o
+		proc_tty.o ipicost.o
 proc-y	+= cmdline.o
 proc-y	+= consoles.o
 proc-y	+= cpuinfo.o
diff --git a/fs/proc/ipicost.c b/fs/proc/ipicost.c
new file mode 100644
index 0000000..967201d
--- /dev/null
+++ b/fs/proc/ipicost.c
@@ -0,0 +1,107 @@
+#include <linux/fs.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/timer.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#define REP_COUNT	100
+
+static int dummy_count;
+static u64 recv_sum;
+
+static void dummy_ipi(void *intime)
+{
+	u64 start, curr;
+	start = (u64)intime;
+	rdtscll(curr);
+	recv_sum += (curr - start);
+	dummy_count++;
+}
+
+static int show_ipicost(struct seq_file *m, void *v)
+{
+	int i;
+	int count;
+	struct call_single_data csd;
+
+	csd.flags = 0;
+	csd.func = &dummy_ipi;
+	csd.info = NULL;
+
+	for_each_online_cpu(i) {
+		u64 start, stop, sum;
+
+		sum = 0;
+		recv_sum = 0;
+		dummy_count = 0;
+		for (count = 0; count < REP_COUNT; count++) {
+			rdtscll(start);
+			csd.info = (void *)start;
+			__smp_call_function_single(i, &csd, 0);
+			rdtscll(stop);
+			sum += (stop - start);
+			msleep(1);
+		}
+		printk("0 CPU %d, time %Lu, recv %Lu, count %d\n", i, sum / REP_COUNT, recv_sum / REP_COUNT, dummy_count);
+	}
+
+	for_each_online_cpu(i) {
+		u64 start, stop, sum;
+
+		sum = 0;
+		recv_sum = 0;
+		dummy_count = 0;
+		for (count = 0; count < REP_COUNT; count++) {
+			rdtscll(start);
+			csd.info = (void *)start;
+			__smp_call_function_single(i, &csd, 1);
+			rdtscll(stop);
+			sum += (stop - start);
+			msleep(1);
+		}
+		printk("1 CPU %d, time %Lu, recv %Lu, count %d\n", i, sum / REP_COUNT, recv_sum / REP_COUNT, dummy_count);
+	}
+	return 0;
+}
+
+static void *c_start(struct seq_file *m, loff_t *pos)
+{
+	return (void *)1;
+}
+
+static void *c_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return NULL;
+}
+
+static void c_stop(struct seq_file *m, void *v)
+{
+}
+
+static const struct seq_operations ipicost_op = {
+	.start	= c_start,
+	.next	= c_next,
+	.stop	= c_stop,
+	.show	= show_ipicost,
+};
+
+static int ipicost_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &ipicost_op);
+}
+
+static const struct file_operations proc_ipicost_operations = {
+	.open		= ipicost_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static int __init proc_ipicost_init(void)
+{
+	proc_create("ipicost", 0, NULL, &proc_ipicost_operations);
+	return 0;
+}
+module_init(proc_ipicost_init);
-- 
1.7.7.3