hackbrary to measure realloc count and duration

README.md

Usage: LD_PRELOAD='/path/to/this/directory/$LIB/ralcount.so' ./Delta-V.x86_64

lib

lib64

lib.c

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include <stdio.h>
#include <dlfcn.h>
#include <stdlib.h>
#include <time.h>
#include <inttypes.h>

#include <gnu/lib-names.h>

// ****************************************************************************

#define NEXT(handle, path, func) ({										\
			static typeof(&func) pfunc = NULL;                           \
			if (!pfunc)                                                  \
				pfunc = (typeof(&func))dlsym(RTLD_NEXT, #func);          \
			if (!pfunc) {                                                \
				if (!handle) {                                           \
					handle = dlopen(path, RTLD_LAZY);                    \
				}                                                        \
				if (!handle) {                                           \
					fprintf(stderr, "ralcount: Ack, dlopen of '%s' failed: %s\n",	\
						path, dlerror());                                \
				}                                                        \
				pfunc = (typeof(&func))dlsym(handle, #func);             \
			}                                                            \
			if (!pfunc) {                                                \
				fprintf(stderr, "ralcount: Ack, dlsym of '%s' (from '%s') failed: %s\n", \
					#func, path, dlerror());                             \
			}                                                            \
			pfunc;                                                       \
		})

static void* libc = NULL;

static int second_counter = 0;
static int64_t second_ns = 0;
static time_t last_second = 0;

void* realloc(void* ptr, size_t size)
{
	time_t curr_second = time(NULL);
	if (curr_second != last_second) {
		printf("%d reallocs - %" PRId64 " ns avg.\n",
			second_counter,
			second_counter ? second_ns / second_counter : -1
		);
		second_counter = 0;
		second_ns = 0;
		last_second = curr_second;
	}

	struct timespec start = {}, end = {};
	clock_gettime(CLOCK_MONOTONIC, &start);
	void* result = NEXT(libc, LIBC_SO, realloc)
		(ptr, size);
	clock_gettime(CLOCK_MONOTONIC, &end);

	second_counter++;
	second_ns += (int64_t)(end.tv_sec - start.tv_sec) * 1000000000 + (end.tv_nsec - start.tv_nsec);

	return result;
}

Makefile

PREFIX=/usr/local
LIB32=lib32
LIB64=lib64

all: lib

lib: lib32/ralcount.so lib64/ralcount.so

lib32:
	mkdir lib32
lib64:
	mkdir lib64

lib32/ralcount.so: lib32 lib.c Makefile
	gcc -m32 -Wall -Wextra -g lib.c -o $@ -fPIC -shared -ldl -D_GNU_SOURCE
lib64/ralcount.so: lib64 lib.c Makefile
	gcc -m64 -Wall -Wextra -g lib.c -o $@ -fPIC -shared -ldl -D_GNU_SOURCE

.PHONY: all lib