[Rd] unexpectedly high memory use in R 2.14.0

[peter dalgaard]

On Apr 12, 2012, at 00:53 , andre zege wrote:

> I recently started using R 2.14.0 on a new machine and i am  experiencing
> what seems like unusually greedy memory use. It happens all the time, but
> to give a specific example, let's say i run the following code
> 
> --------
> 
> for(j in 1:length(files)){
>      load(file.path(dump.dir, files[j]))
>      mat.data[[j]]<-data
> }
> save(abind(mat.data, along=2), file.path(dump.dir, filename))

Hmm, did you preallocate mat.data? If not, you will be copying it repeatedly, and I'm not sure that this can be done by copying pointers only. 

Does it work better with 

mat.data <- lapply(files, function(name) {load(file.path(dump.dir, name); data})

?


> 
> ---------
> 
> It loads parts of multidimensional matrix into a list, then binds it along
> second dimension and saves on disk. Code works, although slowly, but what's
> strange is the amount of memory it uses.
> In particular, each chunk of data is between 50M to 100M, and altogether
> the binded matrix is 1.3G. One would expect that R would use roughly double
> that memory - to keep mat.data and its binded version separately, or 1G. I
> could imagine that for somehow it could use 3 times the size of matrix. But
> in fact it uses more than 5.5 times (almost all of my physical memory) and
> i think is swapping a lot to disk . For this particular task, my top output
> shows eating more than 7G of memory and using up 11G of virtual memory as
> well
> 
> $top
> 
> PID    USER      PR  NI  VIRT    RES  SHR   S %CPU %MEM    TIME+  COMMAND
> 8823  user        25   0  11g     7.2g  10m   R   99.7     92.9
> 5:55.05
> R
> 
> 8590   root       15   0  154m   16m   5948  S  0.5      0.2
> 23:22.40 Xorg
> 
> 
> I have strong suspicion that something is off with my R binary, i don't
> think i experienced things like that in a long time. Is this in line with
> what i am supposed to experience? Are there any ideas for diagnosing what
> is going on?
> Would appreciate any suggestions
> 
> Thanks
> Andre
> 
> 
> ==================================
> 
> Here is what i am running on:
> 
> 
> CentOS release 5.5 (Final)
> 
> 
>> sessionInfo()
> R version 2.14.0 (2011-10-31)
> Platform: x86_64-unknown-linux-gnu (64-bit)
> 
> locale:
> [1] en_US.UTF-8
> 
> attached base packages:
> [1] stats     graphics  grDevices datasets  utils     methods   base
> 
> other attached packages:
> [1] abind_1.4-0       rJava_0.9-3       R.utils_1.12.1    R.oo_1.9.3
> R.methodsS3_1.2.2
> 
> loaded via a namespace (and not attached):
> [1] codetools_0.2-8 tcltk_2.14.0    tools_2.14.0
> 
> 
> 
> I compiled R configure as follows
> /configure --prefix=/usr/local/R --enable-byte-compiled-packages=no
> --with-tcltk --enable-R-shlib=yes
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com