Make cpu_percent() timeout default to 0.0

[giampaolo]

From g.rodola on January 07, 2014 21:00:44

Currently we have 3 functions for calculating CPU percentage:

psutil.Process.get_cpu_percent()
psutil.cpu_percent()
psutil.cpu_times_percent()

All of them have a "timeout" parameter which defaults to 0.1 seconds.
We originally did that because waiting some time was necessary in order to get 
a meaningful return value. 

I've been regretting that decision many times though, because in applications 
which call cpu_percent* repeatedly in a loop it's very easy to forget about 
specifying timeout=0 resulting in dramatic slowdowns which are not immediately 
easy to debug.
Typical example is this, which will take *seconds* to complete:

for p in psutil.process_iter():
    pinfo = {}
    try:
        pinfo['cpu_percent'] = p.cpu_percent()
        # collect other systtem info...
    except psutil.NoSuchProcess:
        pass

Proposal  
is to just have timeout=0.0 by default and make it clear in the doc that if no 
timeout is specified the first call to *cpu_percent() will return a meaningless 
value (0.0).

Original issue: http://code.google.com/p/psutil/issues/detail?id=463

[giampaolo]

From g.rodola on January 07, 2014 12:59:39

Summary: Make cpu_percent() timeout default to 0.0 (was: Make cpu_percent() default to 0.0)

[giampaolo]

From g.rodola on March 09, 2014 15:28:00

Fixed in revision 229c7155fd00 .

Status: FixedInHG
Labels: Milestone-2.0.0

[giampaolo]

From g.rodola on March 10, 2014 04:36:50

Closing out as fixed as 2.0.0 version is finally out.

Status: Fixed