From 6af5001ea05bf5f23c419dc6bed8917f6699139e Mon Sep 17 00:00:00 2001
From: Paul Mackerras <paulus@samba.org>
Date: Fri, 9 Jan 2009 16:26:43 +1100
Subject: [PATCH] --- yaml --- r: 147187 b: refs/heads/master c:
 9abf8a08bc8f18a3b125f834f00e2e71b49c15d2 h: refs/heads/master i:   147185:
 121ce175b653ce081fe73437a7ebe6abb9008071   147183:
 c1d81c39854976fde64a4fb057dd8cba12c25378 v: v3

---
 [refs]                      |  2 +-
 trunk/kernel/perf_counter.c | 20 +++++++++++++++++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index 23be37d44cfb..fb00fd79c943 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ff6f05416ece2caec1a7a1f8180d6598e0ab9272
+refs/heads/master: 9abf8a08bc8f18a3b125f834f00e2e71b49c15d2
diff --git a/trunk/kernel/perf_counter.c b/trunk/kernel/perf_counter.c
index 4be1a8d872b4..b7a027a2ef02 100644
--- a/trunk/kernel/perf_counter.c
+++ b/trunk/kernel/perf_counter.c
@@ -928,18 +928,32 @@ static const struct file_operations perf_fops = {
 
 static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
 {
+	int cpu = raw_smp_processor_id();
+
+	atomic64_set(&counter->hw.prev_count, cpu_clock(cpu));
 	return 0;
 }
 
+static void cpu_clock_perf_counter_update(struct perf_counter *counter)
+{
+	int cpu = raw_smp_processor_id();
+	s64 prev;
+	u64 now;
+
+	now = cpu_clock(cpu);
+	prev = atomic64_read(&counter->hw.prev_count);
+	atomic64_set(&counter->hw.prev_count, now);
+	atomic64_add(now - prev, &counter->count);
+}
+
 static void cpu_clock_perf_counter_disable(struct perf_counter *counter)
 {
+	cpu_clock_perf_counter_update(counter);
 }
 
 static void cpu_clock_perf_counter_read(struct perf_counter *counter)
 {
-	int cpu = raw_smp_processor_id();
-
-	atomic64_set(&counter->count, cpu_clock(cpu));
+	cpu_clock_perf_counter_update(counter);
 }
 
 static const struct hw_perf_counter_ops perf_ops_cpu_clock = {