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Gabriel Staples
www.ElectricRCAircraftGuy.com
26 Sept. 2020
empirically_determine_max_thread_stack_size
You can run this as a C OR C++ program!
References:
1. https://stackoverflow.com/questions/1825964/c-c-maximum-stack-size-of-program/1826072#1826072
1. https://lists.gnu.org/archive/html/bug-coreutils/2009-10/msg00262.html
Originally by Bruno Haible, here, 24 Oct. 2009
I've added some minor changes to it for readability, clarity, and efficiency.
*******************************************************************************/
// =============== Program for determining the default thread stack size =========
// Modified by Gabriel Staples, 26 Sept. 2020
// Originally by Bruno Haible
// 24 Oct. 2009
// Source: https://lists.gnu.org/archive/html/bug-coreutils/2009-10/msg00262.html
#include <alloca.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h> // sleep
/// Thread function to repeatedly allocate memory within a thread, printing
/// the total memory allocated each time, until the program crashes. The last
/// value printed before the crash indicates how big a thread's stack size is.
void* threadfunc(void* bytes_to_allocate_each_loop)
{
const uint32_t BYTES_TO_ALLOCATE_EACH_LOOP =
*(uint32_t*)bytes_to_allocate_each_loop;
uint32_t bytes_allocated = 0;
while (true)
{
printf("bytes_allocated = %u\n", bytes_allocated);
fflush(stdout);
// NB: it appears that you don't necessarily need `volatile` here,
// but you DO definitely need to actually use (ex: write to) the
// memory allocated by `alloca()`, as we do below, or else the
// `alloca()` call does seem to get optimized out on some systems,
// making this whole program just run infinitely forever without
// ever hitting the expected segmentation fault.
volatile uint8_t * byte_buff =
(volatile uint8_t *)alloca(BYTES_TO_ALLOCATE_EACH_LOOP);
byte_buff[0] = 0;
bytes_allocated += BYTES_TO_ALLOCATE_EACH_LOOP;
}
}
int main()
{
const uint32_t BYTES_TO_ALLOCATE_EACH_LOOP = 128;
pthread_t thread;
pthread_create(&thread, NULL, threadfunc,
(void*)(&BYTES_TO_ALLOCATE_EACH_LOOP));
while (true)
{
const unsigned int SLEEP_SEC = 10000;
sleep(SLEEP_SEC);
}
return 0;
}
/*
Sample output:
bytes_allocated = 7449856
bytes_allocated = 7449984
bytes_allocated = 7450112
bytes_allocated = 7450240
bytes_allocated = 7450368
bytes_allocated = 7450496
bytes_allocated = 7450624
bytes_allocated = 7450752
bytes_allocated = 7450880
Segmentation fault (core dumped)
*/
