reading information about how to increase stack size for a c++ application compiled with gnu, at com开发者_如何学Pythonpilation time, I understood that it can be done with setrlimit at the beginning of the program. Nevertheless I could not find any successful example on how to use it and in which part of the program apply it in order to get a 64M stack size for a c++ program, could anybody help me?
Thanlks
Normally you would set the stack size early on, e,g, at the start of main()
, before calling any other functions. Typically the logic would be:
- call
getrlimit
to get current stack size - if current size < required stack size then
- call
setrlimit
to increase stack size to required size
- call
In C that might be coded something like this:
#include <sys/resource.h>
#include <stdio.h>
int main (int argc, char **argv)
{
const rlim_t kStackSize = 64L * 1024L * 1024L; // min stack size = 64 Mb
struct rlimit rl;
int result;
result = getrlimit(RLIMIT_STACK, &rl);
if (result == 0)
{
if (rl.rlim_cur < kStackSize)
{
rl.rlim_cur = kStackSize;
result = setrlimit(RLIMIT_STACK, &rl);
if (result != 0)
{
fprintf(stderr, "setrlimit returned result = %d\n", result);
}
}
}
// ...
return 0;
}
See if the runtime execution maximum is limiting it:
[wally@zf conf]$ ulimit -all
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 16114
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 16114
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
Note that the stack size, by default, is limited to 10 MiB. So to increase it to 64 MiB:
[wally@zf conf]$ ulimit -s 64M
-bash: ulimit: 64M: invalid number
[wally@zf conf]$ ulimit -s 65536
[wally@zf conf]$ ulimit -all
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 16114
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 65536
cpu time (seconds, -t) unlimited
max user processes (-u) 16114
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
To get beyond the hard limit in setrlimit (on OSX its only 64MB by default), create a new thread using pthreads with a stack size of your choice. Here's a C snippet:
// Call function f with a 256MB stack.
static int bigstack(void *(*f)(void *), void* userdata) {
pthread_t thread;
pthread_attr_t attr;
// allocate a 256MB region for the stack.
size_t stacksize = 256*1024*1024;
pthread_attr_init(&attr);
pthread_attr_setstacksize(&attr, stacksize);
int rc = pthread_create(&thread, &attr, f, userdata);
if (rc){
printf("ERROR: return code from pthread_create() is %d\n", rc);
return 0;
}
pthread_join(thread, NULL);
return 1;
}
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