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Holger Hans Peter Freyther authored
Avoid memory allocations to construct the path for files in the procfs. The procfs paths are way shorter than the PATH_MAX so we can use snprintf on a string located on the stack. This shows up as a win on x86 using the benchmark program below. $ make libsystemd-shared.la; gcc -O2 -Isrc/systemd/ -Isrc/ \ -o simple-perf-test simple-perf-test.c \ .libs/libsystemd-shared.a -lrt #include "shared/util.h" void test_once(void) { pid_t pid = getpid(); char *tmp = NULL; get_process_comm(pid, &tmp); free(tmp); tmp = NULL; get_process_cmdline(pid, 0, 1, &tmp); free(tmp); is_kernel_thread(pid); tmp = NULL; get_process_exe(pid, &tmp); free(tmp); } int main(int argc, char **argv) { int i; for (i = 0; i < 50000; ++i) test_once(); }
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