---

yaml --- r: 304891 b: refs/heads/master c: 7caaf4d h: refs/heads/master i: 304889: 5558528 304887: 26fe21c v: v3
git-mirror · May 9, 2012 · 6fdcb26 · 6fdcb26
1 parent ab9ad42
commit 6fdcb26
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Showing 2 changed files with 14 additions and 3 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: fc006cf7cc7471e1bdf34e40111971e03622af6c
+refs/heads/master: 7caaf4d8241feecafb87919402b0a6dbb1b71d9e
diff --git a/trunk/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/trunk/arch/x86/kernel/cpu/perf_event_amd_ibs.c
@@ -85,8 +85,19 @@ perf_event_set_period(struct hw_perf_event *hwc, u64 min, u64 max, u64 *hw_perio
 		overflow = 1;
 	}
 
-	if (left > max)
-		left = max;
+	/*
+	 * If the hw period that triggers the sw overflow is too short
+	 * we might hit the irq handler. This biases the results.
+	 * Thus we shorten the next-to-last period and set the last
+	 * period to the max period.
+	 */
+	if (left > max) {
+		left -= max;
+		if (left > max)
+			left = max;
+		else if (left < min)
+			left = min;
+	}
 
 	*hw_period = (u64)left;