From hadley at rice.edu  Sun May 15 15:07:19 2011
From: hadley at rice.edu (Hadley Wickham)
Date: Sun, 15 May 2011 08:07:19 -0500
Subject: [Rd] RProfmem output format
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Also, would you mind commenting how RProfmem is misleading?

There are three ways to profile memory use over time in R code. ...
All can be misleading, for different reasons.
--- http://cran.r-project.org/doc/manuals/R-exts.html#Profiling-R-code-for-memory-use

The other two ways describe why they are misleading.

Hadley

On Sun, May 15, 2011 at 8:02 AM, Hadley Wickham <hadley at rice.edu> wrote:
>>> In the subsequence lines I'm assuming the structure is bytes allocated : call.
>>
>> I think the five numbers come from four memory allocations before
>> example() is called. ?Looking at the code in src/main/memory.c, it
>> prints newline only when the call stack is not empty.
>
> Looking into that example in more detail, here's the distribution of
> allocation numbers:
>
> ? 1 ? ?3 ? ?4
> 4621 ? 30 ? ?2
>
> (with a threshold of 5k)
>
> So it happens ~30 times in total.
>
> So what causes allocations when the call stack is empty? ?Something
> internal? ?Does the garbage collector trigger allocations (i.e. could
> it be caused by moving data to contiguous memory)?
>
> Any ideas what the correct thing to do with these memory allocations?
> Ignore them because they're not really related to the function they're
> attributed to? ?Sum them up?
>
>> I don't see why this is done, and I may well be the person who did it
>> (I don't have svn on this computer to check), but it is clearly
>> deliberate.
>
> It seems like it would be more consistent to always print a newline,
> and then it would obvious those allocations occurred when the call
> stack was empty. ?This would make parsing the file a little bit
> easier.
>
> Hadley
>
> --
> Assistant Professor / Dobelman Family Junior Chair
> Department of Statistics / Rice University
> http://had.co.nz/
>



-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/



[Rd] RProfmem output format
Hadley Wickham