Rprof {utils}R Documentation

Enable Profiling of R's Execution

Description

Enable or disable profiling of the execution of R expressions.

Usage

Rprof(filename = "Rprof.out", append = FALSE, interval = 0.02,
       memory.profiling = FALSE, gc.profiling = FALSE, 
       line.profiling = FALSE, numfiles = 100L, bufsize = 10000L)

Arguments

filename

The file to be used for recording the profiling results. Set to NULL or "" to disable profiling.

append

logical: should the file be over-written or appended to?

interval

real: time interval between samples.

memory.profiling

logical: write memory use information to the file?

gc.profiling

logical: record whether GC is running?

line.profiling

logical: write line locations to the file?

numfiles, bufsize

integers: line profiling memory allocation

Details

Enabling profiling automatically disables any existing profiling to another or the same file.

Profiling works by writing out the call stack every interval seconds, to the file specified. Either the summaryRprof function or the wrapper script R CMD Rprof can be used to process the output file to produce a summary of the usage; use R CMD Rprof --help for usage information.

How time is measured varies by platform: on a Unix-alike it is the CPU time of the R process, so for example excludes time when R is waiting for input or for processes run by system to return.

Note that the timing interval cannot usefully be too small: once the timer goes off, the information is not recorded until the next timing click (probably in the range 1–10msecs).

Functions will only be recorded in the profile log if they put a context on the call stack (see sys.calls). Some primitive functions do not do so: specifically those which are of type "special" (see the ‘R Internals’ manual for more details).

Individual statements will be recorded in the profile log if line.profiling is TRUE, and if the code being executed was parsed with source references. See parse for a discussion of source references. By default the statement locations are not shown in summaryRprof, but see that help page for options to enable the display.

Note

Profiling is not available on all platforms. By default, support for profiling is compiled in if possible – configure R with --disable-R-profiling to change this.

As R profiling uses the same mechanisms as C profiling, the two cannot be used together, so do not use Rprof in an executable built for C-level profiling.

Note

The profiler interrupts R asynchronously, and it cannot allocate memory to store results as it runs. This affects line profiling, which needs to store an unknown number of file pathnames. The numfiles and bufsize arguments control the size of pre-allocated buffers to hold these results: the former counts the maximum number of paths, the latter counts the numbers of bytes in them. If the profiler runs out of space it will skip recording the line information for new files, and issue a warning when Rprof(NULL) is called to finish profiling.

See Also

The chapter on “Tidying and profiling R code” in “Writing R Extensions” (see the ‘doc/manual’ subdirectory of the R source tree).

summaryRprof to analyse the output file.

tracemem, Rprofmem for other ways to track memory use.

Examples

## Not run: Rprof()
## some code to be profiled
Rprof(NULL)
## some code NOT to be profiled
Rprof(append = TRUE)
## some code to be profiled
Rprof(NULL)
\dots
## Now post-process the output as described in Details

## End(Not run)

[Package utils version 3.2.2 Index]