Document background noise of RX packets from bridges (RHBZ#647987).

[virt-top.git] / virt-top / virt-top.pod

diff --git a/virt-top/virt-top.pod b/virt-top/virt-top.pod
old mode 100644 (file)
new mode 100755 (executable)
index a708357..4d7df4e
--- a/virt-top/virt-top.pod
+++ b/virt-top/virt-top.pod
@@ -46,6 +46,14 @@ Batch mode.  In this mode keypresses are ignored.
 Connect to URI given.  The default is to connect to the Xen
 hypervisor.
 
+To connect to QEMU/KVM you would normally do I<-c qemu:///system>
+
+To connect to libvirtd on a remote machine you would normally do
+I<-c xen://host/>
+
+Full details on connection URIs is available at
+L<http://libvirt.org/uri.html>
+
 =item B<-d delay>
 
 Set the delay between screen updates in seconds.
@@ -61,7 +69,7 @@ is to run continuously.
 
 Set the sort order to one of:
 B<cpu> (sort by %CPU used),
-B<mem> (sort by memory used),
+B<mem> (sort by total memory),
 B<time> (sort by total time),
 B<id> (sort by domain ID),
 B<name> (sort by domain name),
@@ -188,6 +196,10 @@ for details).
 
 Display usage summary.
 
+=item B<--version>
+
+Display version number and exit.
+
 =back
 
 =head1 KEYS
@@ -240,7 +252,8 @@ Sort by %CPU.
 
 =item I<M>
 
-Sort by memory.
+Sort by total memory.  Note that this shows the total memory
+allocated to the guest, not the memory being used.
 
 =item I<T>
 
@@ -352,19 +365,32 @@ init file.
 
 =back
 
-
 Note that in the current implementation, options specified in
 the init file override options specified on the command line.
 This is a bug and this behaviour may change in the future.
 
+=head1 NOTES
+
+=head2 NETWORK RX BYTES AND PACKETS
+
+Libvirt/virt-top has no way to know that a packet transmitted to a
+guest was received (eg. if the guest is not listening).  In the
+network RX stats, virt-top reports the packets transmitted to the
+guest, on the basis that the guest might receive them.
+
+In particular this includes broadcast packets.  Because of the way
+that Linux bridges work, if the guest is connected to a bridge, it
+will probably see a steady "background noise" of RX packets even when
+the network interface is idle or down.  These are caused by STP
+packets generated by the bridge.
+
 =head1 SEE ALSO
 
 L<top(1)>,
 L<virsh(1)>,
-L<xm(1)>,
-L<xentop(1)>,
+L<http://www.libvirt.org/ocaml/>,
 L<http://www.libvirt.org/>,
-L<http://et.redhat.com/~rjones/>,
+L<http://people.redhat.com/~rjones/>,
 L<http://caml.inria.fr/>
 
 =head1 AUTHORS
@@ -373,7 +399,7 @@ Richard W.M. Jones <rjones @ redhat . com>
 
 =head1 COPYRIGHT
 
-(C) Copyright 2007 Red Hat Inc., Richard W.M. Jones
+(C) Copyright 2007-2011 Red Hat Inc., Richard W.M. Jones
 http://libvirt.org/
 
 This program is free software; you can redistribute it and/or modify
@@ -416,9 +442,12 @@ should submit with your bug report.
 
 =item 3. Get version of virt-top and version of libvirt.
 
-In virt-top, press the I<h> (help) key, and write down the version of
-virt-top and the version of libvirt.  They are shown in the first
-line.
+Use:
+
+ virt-top --version
+
+If you can get the precise version of libvirt you are using
+then that too is helpful.
 
 =item 4. Submit a bug report.
 
@@ -435,5 +464,3 @@ spaces).  You can also send me an email with the bug number if you
 want a faster response.
 
 =back
-
-=end