[PATCH] Add documentation for /proc/stat

From: "Bryan O'Sullivan" <bos@serpentine.com>

This patch adds documentation for the contents of the /proc/stat file.

Documentation/filesystems/proc.txt

@@ -25,6 +25,7 @@ Table of Contents
   1.5	SCSI info
   1.6	Parallel port info in /proc/parport
   1.7	TTY info in /proc/tty
+  1.8	Miscellaneous kernel statistics in /proc/stat
 
   2	Modifying System Parameters
   2.1	/proc/sys/fs - File system data
@@ -704,6 +705,58 @@ To see  which  tty's  are  currently in use, you can simply look into the file
   unknown              /dev/tty        4    1-63 console 
 
 
+1.8 Miscellaneous kernel statistics in /proc/stat
+-------------------------------------------------
+
+Various pieces   of  information about  kernel activity  are  available in the
+/proc/stat file.  All  of  the numbers reported  in  this file are  aggregates
+since the system first booted.  For a quick look, simply cat the file:
+
+  > cat /proc/stat
+  cpu  2255 34 2290 22625563 6290 127 456
+  cpu0 1132 34 1441 11311718 3675 127 438
+  cpu1 1123 0 849 11313845 2614 0 18
+  intr 114930548 113199788 3 0 5 263 0 4 [... lots more numbers ...]
+  ctxt 1990473
+  btime 1062191376
+  processes 2915
+  procs_running 1
+  procs_blocked 0
+
+The very first  "cpu" line aggregates the  numbers in all  of the other "cpuN"
+lines.  These numbers identify the amount of time the CPU has spent performing
+different kinds of work.  Time units are in USER_HZ (typically hundredths of a
+second).  The meanings of the columns are as follows, from left to right:
+
+- user: normal processes executing in user mode
+- nice: niced processes executing in user mode
+- system: processes executing in kernel mode
+- idle: twiddling thumbs
+- iowait: waiting for I/O to complete
+- irq: servicing interrupts
+- softirq: servicing softirqs
+
+The "intr" line gives counts of interrupts  serviced since boot time, for each
+of the  possible system interrupts.   The first  column  is the  total of  all
+interrupts serviced; each  subsequent column is the  total for that particular
+interrupt.
+
+The "ctxt" line gives the total number of context switches across all CPUs.
+
+The "btime" line gives  the time at which the  system booted, in seconds since
+the Unix epoch.
+
+The "processes" line gives the number  of processes and threads created, which
+includes (but  is not limited  to) those  created by  calls to the  fork() and
+clone() system calls.
+
+The  "procs_running" line gives the  number of processes  currently running on
+CPUs.
+
+The   "procs_blocked" line gives  the  number of  processes currently blocked,
+waiting for I/O to complete.
+
+
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 Summary
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