Hi guys
I have some C/C++ programs that use very odd memory usage. I have made a
small replica below
(it can also be taken from http://pastebin.com/1ammgpCE)
Save e.g. as memfun.c
In the C-code I generate 20 peaks of very short memory peaks, and you
can compile (on Linux) and run as this:
gcc -o memfun memfun.c -lm
valgrind --tool=massif --massif-out-file=massif.out ./memfun
massif-visualizer massif.out
or
ms_print massif.out > massif.txt; less massif.txt)
(BTW; Thanx to the maintainers of massif-visualizer - this rocks)
However with the standard settings I only get 3 memory peaks detected -
not 20.
Obviously I can tweak --threshold= and --peak-inaccuracy= but it seems
that
I in general can be sure that I can catch all peaks. Please comment :-)
Are these something that I miss here? Are there other tools that are
better suited for
detecting memory peaks like this memory-hedgehog....
Thanx mates
Best
Peter
----------------
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
/*
Demo program:
gcc -o memfun memfun.c -lm
valgrind --tool=massif --massif-out-file=massif.out ./memfun
massif-visualizer massif.out
(or ms_print massif.out > massif.txt; less massif.txt)
*/
int main(void)
{
int ii,jj;
int *pt;
int *pt2;
float ac;
int numberOfPeaks = 0;
for (ii=0;ii<100;ii++) {
/* Allocate some small linearly increasing memory block */
pt = (int *)malloc((1000*ii+1)*sizeof(int));
if (ii%5 == 0) {
/* Allocate some gigantic memory block - but only every 10th
iteration */
pt2 = (int *)malloc((1000000)*sizeof(int));
printf("Allocating large memory block\n");
numberOfPeaks++;
} else {
/* Allocate just one element for every 9/10 iteration */
pt2 = (int *)malloc((1)*sizeof(int));
}
/* Put in data and print it */
pt2[0] = ii;
printf(" Found value %i\n",pt2[0]);
/* Free the memory - note that the peak */
free(pt2);
/* Spend time on "something" - the actual work does not matter*/
ac = 1;
for (jj=0;jj<10000*(1 + ii);jj++) {
ac += sin(jj*0.01) + cos(jj*0.01 + 0.3);
}
printf(" Found dummy value %f\n",ac);
/* Free the memory */
free(pt);
}
printf("I made %i memory peaks\n",numberOfPeaks);
return 0;
}
--
Peter Toft <p...@linuxbog.dk>
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