I'm using remote unwinding to get the call chain of a "remote" process, I found it a little slower than I expected。 It needs 0.04 seconds to do one backtrace, while using local unwinding, it just need 0.0002 seconds to do one backtrace.
why remote unwinding is so much slower than local unwinding, is there any way to speed up the remote unwinding? actually the target process is in the same machine.
below is my code using libunwind. I will be appreciate for any suggestions.
static unw_addr_space_t as;
static struct UPT_info *ui;
void do_traceback()
{
unw_cursor_t c;
unw_word_t ip, sp;
int ret;
unw_init_remote(&c, as, ui);
ret = unw_step(&c);
while(ret > 0)
{
unw_get_reg(&c, UNW_REG_IP, &ip);
unw_get_reg(&c, UNW_REG_SP, &sp);
printf("ip = %lx, sp = %lx\n", (long) ip, (long) sp);
ret = unw_step(&c);
}
}
void main(int argc, char *argv[])
{
as = unw_create_addr_space(&_UPT_accessors, 0);
ui = _UPT_create(pid);
attach_process(pid);
do_traceback();
detach_process(pid);
}