cgtop: major modernizations

In preparation of the unified cgroup support, let's clean up cgtop:

a) rework time code to be based on "nsec_t" rather than "struct timespec"

b) Introduce long option --order= for selecting ordering

c) count number of processes only in the main hierarchy, don't bother
   with the controller hierarchies. We don't allow orthogonal
   hierarchies in systemd anymore, hence there's no point to check the
   other hierarchies.

d) Deal with non-monotonic cpuacct values (see #749)

e) When sorting groups, don't do prefix compare when ordering by number
   of tasks, since this is not accumulative for all children.

f) Actually make --cpu without parameter work

g) Don't output control characters when we get them as input.

Fixes #749.

1 files changed, 21 insertions, 8 deletions

diff --git a/man/systemd-cgtop.xml b/man/systemd-cgtop.xml
index d4b041a1f9..e4bc22f278 100644
--- a/man/systemd-cgtop.xml
+++ b/man/systemd-cgtop.xml
@@ -1,4 +1,4 @@
-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
 
@@ -64,10 +64,10 @@
     regular intervals (by default every 1s), similar in style to
     <citerefentry project='man-pages'><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
 
-    <para>If <command>systemd-cgtop</command> is not connected to a tty, no
-    column headers are printed and the default is to only run one iteration.
-    The <varname>--iterations</varname> argument, if given, is still honored.
-    This mode is suitable for scripting.</para>
+    <para>If <command>systemd-cgtop</command> is not connected to a
+    tty, no column headers are printed and the default is to only run
+    one iteration.  The <varname>--iterations=</varname> argument, if
+    given, is honored. This mode is suitable for scripting.</para>
 
     <para>Resource usage is only accounted for control groups in the
     relevant hierarchy, i.e. CPU usage is only accounted for control
@@ -104,6 +104,7 @@
     <variablelist>
       <varlistentry>
         <term><option>-p</option></term>
+        <term><option>--order=path</option></term>
 
         <listitem><para>Order by control group
         path name.</para></listitem>
@@ -111,25 +112,28 @@
 
       <varlistentry>
         <term><option>-t</option></term>
+        <term><option>--order=tasks</option></term>
 
-        <listitem><para>Order by number of tasks in control group
-        (i.e. threads and processes).</para></listitem>
+        <listitem><para>Order by number of processes in control group.</para></listitem>
       </varlistentry>
 
       <varlistentry>
         <term><option>-c</option></term>
+        <term><option>--order=cpu</option></term>
 
         <listitem><para>Order by CPU load.</para></listitem>
       </varlistentry>
 
       <varlistentry>
         <term><option>-m</option></term>
+        <term><option>--order=memory</option></term>
 
         <listitem><para>Order by memory usage.</para></listitem>
       </varlistentry>
 
       <varlistentry>
         <term><option>-i</option></term>
+        <term><option>--order=io</option></term>
 
         <listitem><para>Order by disk I/O load.</para></listitem>
       </varlistentry>
@@ -140,7 +144,7 @@
 
         <listitem><para>Run in "batch" mode: do not accept input and
         run until the iteration limit set with
-        <option>--iterations</option> is exhausted or until killed.
+        <option>--iterations=</option> is exhausted or until killed.
         This mode could be useful for sending output from
         <command>systemd-cgtop</command> to other programs or to a
         file.</para></listitem>
@@ -156,6 +160,15 @@
       </varlistentry>
 
       <varlistentry>
+        <term><option>--cpu=percentage</option></term>
+        <term><option>--cpu=time</option></term>
+
+        <listitem><para>Controls whether the CPU usage is shown as
+        percentage or time. By default the CPU usage is shown as
+        percentage.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><option>-n</option></term>
         <term><option>--iterations=</option></term>