top: document 2 fields for displaying autogroup values

[ we'll also eliminate a couple of references to the ]
[ repurposed 'F' command which should have gone away ]
[ with the introduction of that new 'focus' feature! ]

Signed-off-by: Jim Warner <james.warner@comcast.net>

top/top.1

@@ -590,7 +590,7 @@ This table may help in interpreting the scaled values displayed:
 Listed below are \*(We's available process fields (columns).
 They are shown in strict ascii alphabetical order.
 You may customize their position and whether or not they are displayable
-with the `f' or `F' (Fields Management) \*(CIs.
+with the `f' (Fields Management) \*(CI.
 
 Any field is selectable as the sort field, and you control whether they
 are sorted high-to-low or low-to-high.
@@ -630,6 +630,30 @@ A task's currently resident share of available \*(MP.
 
 \*(XX.
 
+.TP 4
+\fBAGID \*(Em Autogroup Identifier \fR
+The autogroup identifier associated with a process.
+This feature operates in conjunction with the CFS scheduler
+to improve interactive desktop performance.
+
+When /proc/sys/kernel/sched_autogroup_enable is set, a new
+autogroup is created with each new session (\*(Xa SID).
+All subsequently forked processes in that session inherit membership in
+this autogroup.
+The kernel then attempts to equalize distribution of CPU cycles
+across such groups.
+Thus, an autogroup with many \*(PU intensive processes (e.g make -j)
+will not dominate an autogroup with only one or two processes.
+
+When -1 is displayed it means this information is not available.
+
+.TP 4
+\fBAGNI \*(Em Autogroup Nice Value \fR
+The autogroup nice value which affects scheduling of all processes
+in that group.
+A negative nice value means higher priority, whereas a positive nice
+value means lower priority.
+
 .TP 4
 \fBCGNAME \*(Em Control Group Name \fR
 The name of the control group to which a process belongs,
@@ -756,6 +780,10 @@ means lower priority.
 Zero in this field simply means priority will not be adjusted in determining
 a task's dispatch-ability.
 
+\*(NT This value only affects scheduling priority relative to other processes
+in the same autogroup.
+\*(XC `AGID' and `AGNI' fields for additional information on autogroups.
+
 .TP 4
 \fBNU \*(Em Last known NUMA node \fR
 A number representing the NUMA node associated with the last used processor (`P').
@@ -1131,7 +1159,7 @@ last update (see nMin).
 .\" ......................................................................
 .SS 3b. MANAGING Fields
 .\" ----------------------------------------------------------------------
-After pressing the \*(CI `f' or `F' (Fields Management) you will be presented
+After pressing the \*(CI `f' (Fields Management) you will be presented
 with a screen showing: 1) the \*(CW name; 2) the designated sort field;
 3) all fields in their current order along with descriptions.
 Entries marked with an asterisk are the currently displayed fields,