ionice - get/set process IO priority

[giampaolo]

From g.rodola on January 12, 2011 14:11:22

I've just found this interesting article: 
http://friedcpu.wordpress.com/2007/07/17/why-arent-you-using-ionice-yet/ 
...describing how, on Linux, the "renice" command can be used to change the IO 
priority of a process.
Proposal  
is to add this functionality in psutil by adding a new property to the Process 
class which permits to  get and set/change process IO priority.

= API = 

This should be the same we used for process niceness/priority ( issue 142 ), 
consisting in a unique property for both getting and setting process IO priority.
IOPRIO_CLASS_RT, IOPRIO_CLASS_BE and IOPRIO_CLASS_IDLE constants should be 
exposed as well.
Example:

>>> psutil.Process(os.getpid())
>>> psutil.ionice
0
>>> psutil.ionice = psutil.IOPRIO_CLASS_RT
>>> psutil.ionice
2

= Linux implementation = 

renice source code: 
http://www.kernel.org/pub/linux/utils/util-linux-ng/v2.19/util-linux-2.19-rc1.tar.gz
 ioprio_get() and ioprio_set() system calls: 
http://linux.die.net/man/2/ioprio_get http://linux.die.net/man/2/ioprio_set = 
Other platforms = 

FreeBSD (and probably OSX as well) seems not to have this functionnality yet 
although it might appear in the future: 
http://old.nabble.com/ionice-in-FreeBSD--td27424108.html On Windows this seems 
to be possible but only starting from Windows Vista: 
http://forum.sysinternals.com/printer_friendly_posts.asp?TID=12767 As for now, 
my proposal is to provide this functionnality only on Linux.
On all other platforms Process.nice will just raise an AttributeError exception.

Original issue: http://code.google.com/p/psutil/issues/detail?id=147

[giampaolo]

From g.rodola on January 13, 2011 02:45:21

Cc: guichaz

[giampaolo]

From g.rodola on January 13, 2011 14:25:50

Implemented in r892 .
I decided not to use a property but to split everything in two separate 
functions, get_ionice() and set_ionice(), because it must be possible to 
differentiate priority class and level (see ionice command).

Status: FixedInSVN

[giampaolo]

From g.rodola on March 20, 2011 14:55:37

Status: Fixed

[giampaolo]

From g.rodola on March 02, 2013 03:58:12

Updated csets after the SVN -> Mercurial migration: r892 == revision 
d17f087b01e3