diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index 3b313a2b9..7e15cf03b 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -24,7 +24,7 @@
 .\" This document is based on the perf_event.h header file, the
 .\" tools/perf/design.txt file, and a lot of bitter experience.
 .\"
-.TH PERF_EVENT_OPEN 2 2014-04-06 "Linux" "Linux Programmer's Manual"
+.TH PERF_EVENT_OPEN 2 2014-04-10 "Linux" "Linux Programmer's Manual"
 .SH NAME
 perf_event_open \- set up performance monitoring
 .SH SYNOPSIS
@@ -2386,13 +2386,17 @@ it was expecting.
 Returned when the requested event requires root permissions
 (or a more permissive perf_event paranoid setting).
 Some common causes are attaching to a process owned by a different user,
-monitoring all processes on a given cpu,
-or not setting exclude_kernel and the paranoid setting requires it.
+monitoring all processes on a given CPU,
+or not setting
+.I exclude_kernel
+and the paranoid setting requires it.
 .TP
 .B EBADF
 Returned if the
 .I group_fd
-file descriptor is not valid, or, if PERF_FLAG_PID_CGROUP is set,
+file descriptor is not valid, or, if
+.B PERF_FLAG_PID_CGROUP
+is set,
 the cgroup file descriptor in
 .I pid
 is not valid.
@@ -2407,25 +2411,25 @@ Returned if the specified event is invalid.
 There are many possible reasons for this.
 A not-exhaustive list:
 .I sample_freq
-higher than the maximum setting,
+is higher than the maximum setting;
 the
 .I cpu
-to monitor does not exist,
+to monitor does not exist;
 .I read_format
-is out of range,
+is out of range;
 .I sample_type
-is out of range,
+is out of range;
 the
 .I flags
-value is out of range,
+value is out of range;
 .I exclusive
 or
 .I pinned
-set and the event is not a group leader,
+set and the event is not a group leader;
 the event
 .I config
-values are out of range or set reserved bits,
-the generic event selected is not supported, or
+values are out of range or set reserved bits;
+the generic event selected is not supported; or
 there is not enough room to add the selected event.
 .TP
 .B EMFILE
@@ -2436,24 +2440,24 @@ events can be created.
 .TP
 .B ENODEV
 Returned when the event involves a feature not supported
-by the current cpu.
+by the current CPU.
 .TP
 .B ENOENT
 Returned if the
 .I type
 setting is not valid.
-Also returned for
+This error is also returned for
 some unsupported generic events.
 .TP
 .B ENOSPC
 Prior to Linux 3.3, if there was not enough room for the event,
 .B ENOSPC
 was returned.
-Linus did not like this, and this was changed to
+In Linux 3.3, this was changed to
 .BR EINVAL .
 .B ENOSPC
 is still returned if you try to add more breakpoint events
-than supported by hardware.
+than supported by the hardware.
 .TP
 .B ENOSYS
 Returned if