From c3c0b7197fb2459233e7e115177d808dd7c2233b Mon Sep 17 00:00:00 2001
From: Masamichi Takagi <masamichi.takagi@riken.jp>
Date: Fri, 27 Mar 2020 02:12:04 -0400
Subject: [PATCH] test: perf: prevent overflow counter from stopping counter

Fixes: 1a204b6 "perf: overflow test"
Change-Id: I4d8e93b97f7a8d58ef7811f55b5c995b16c5af69
---
 test/perf_overflow/combination_test.c | 26 ++++++++++++++++++++++++++
 test/perf_overflow/perf_common.c      |  7 +++++--
 test/perf_overflow/perf_common.h      |  1 +
 3 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/test/perf_overflow/combination_test.c b/test/perf_overflow/combination_test.c
index 33e293d6..91b97f45 100644
--- a/test/perf_overflow/combination_test.c
+++ b/test/perf_overflow/combination_test.c
@@ -1,5 +1,6 @@
 /* combination_test.c COPYRIGHT FUJITSU LIMITED 2019 */
 #include "combination_test.h"
+#include "perf_common.h"
 
 //
 // main
@@ -32,6 +33,31 @@ static int combination_test(struct command_set *cmd_set)
 		goto out;
 	}
 
+	/* Set reasonable value to overflow counter so as not to stop
+	 * counter on Linux. Reset must precede to prevent
+	 * uninitialized value is accumulated on McKernel for the case
+	 * REFRESH includes ENABLE
+	 */
+	ret = perf_event_ioc_refresh(fd, NULL);
+	if (ret < 0) {
+		perror("perf_event_ioc_refresh");
+		goto out;
+	}
+
+	/* Stop counter for the case REFRESH includes ENABLE */
+	ret = asm_ioctl3(fd, PERF_EVENT_IOC_DISABLE, 0);
+	if (ret < 0) {
+		errno = -ret;
+		perror("asm_ioctl(PERF_EVENT_IOC_DISABLE)");
+		goto out;
+	}
+
+	ret = ioctl(fd, PERF_EVENT_IOC_RESET, 0);
+	if (ret < 0) {
+		perror("ioctl(PERF_EVENT_IOC_RESET)");
+		goto out;
+	}
+
 	ret = asm_ioctl3(fd, PERF_EVENT_IOC_ENABLE, 0);
 	if (ret < 0) {
 		errno = -ret;
diff --git a/test/perf_overflow/perf_common.c b/test/perf_overflow/perf_common.c
index e53f076b..7c2e5f76 100644
--- a/test/perf_overflow/perf_common.c
+++ b/test/perf_overflow/perf_common.c
@@ -164,9 +164,12 @@ static void build_perf_event_ioc_reset(struct command *cmd)
 }
 
 // perf_event_ioc_refresh command
-static int perf_event_ioc_refresh(int fd, void *_args)
+int perf_event_ioc_refresh(int fd, void *_args)
 {
-	int ret = asm_ioctl3(fd, PERF_EVENT_IOC_REFRESH, 0);
+	/* Prevent overflow counter from stopping counter
+	 * Note that it starts counter as well
+	 */
+	int ret = asm_ioctl3(fd, PERF_EVENT_IOC_REFRESH, 256);
 
 	if (ret < 0) {
 		errno = -ret;
diff --git a/test/perf_overflow/perf_common.h b/test/perf_overflow/perf_common.h
index f72f2551..d0ebbcee 100644
--- a/test/perf_overflow/perf_common.h
+++ b/test/perf_overflow/perf_common.h
@@ -25,6 +25,7 @@ void print_usage(void);
 //system call
 long perf_event_open(struct perf_event_attr *event_attr, pid_t pid,
 			int cpu, int group_fd, unsigned long flags);
+int perf_event_ioc_refresh(int fd, void *_args);
 int init_perf_event_attr(struct perf_event_attr *event_attr);
 int asm_ioctl3(int fd, unsigned long arg1, unsigned long arg2);
 int asm_read(int fd, void *buf, size_t size);