[R] Huge difference btw system time and elapsed time

R. Michael Weylandt michael.weylandt at gmail.com
Wed Feb 22 04:11:19 CET 2012


The time relationships aren't strictly linear between any of the three
measures, but *very generally* I've interpreted them as something
like:

User: stuff you do (i.e., doing all the commands)
System: stuff at the OS level (memory allocations and whatnot)
Elapsed: Clock time

None is a great measure in isolation, but the system time is not the
worrisome one here: it looks like your script takes about a day and a
half to run....that might be ok (and perhaps unavoidable) but it looks
like there might be value in trying to squeeze some speed out of your
script. A simple thing like byte-compiling that gives 2x speedup would
be huge here.

Michael

On Tue, Feb 21, 2012 at 10:06 PM, Libo Sun <libosun at rams.colostate.edu> wrote:
> Hi all,
>
> I got this time for my code,
>
>> proc.time()-pt
>      user     system    elapsed
> 132541.743      0.004 132533.526
>
> As you can see, there is huge difference btw elapsed time and system time.
> Does that mean lots of I/O? Or some bad coding?
>
> Thanks,
> Libo
>
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>
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