PERF_EFLAGS_EXACT
regs.flags &= ~PERF_EFLAGS_EXACT;
regs.flags |= PERF_EFLAGS_EXACT;
if (regs->flags & PERF_EFLAGS_EXACT)
regs->flags = pebs->flags & ~PERF_EFLAGS_EXACT;
regs->flags |= PERF_EFLAGS_EXACT;
regs->flags |= PERF_EFLAGS_EXACT;
regs->flags = PERF_EFLAGS_EXACT;
regs->flags &= ~PERF_EFLAGS_EXACT;