![]() | |||||||||||||
Messages in this thread |
Lahti Oy wrote: > > Small patch that makes NR_CPUS loops decrement from 31 to 0 in sched.c to > squeeze out some cycles (of course only on SMP machines). Also deprecated a > macro that was only used once in the code and changed one if-conditional to > else if.> > ...> > - for (i = 0; i < NR_CPUS; i++) > + for (i = NR_CPUS; i; i--) > sum += cpu_rq(i)->nr_running; Off-by-one there. You'd want for (i = NR_CPUS; --i >= 0; ) or something similarly foul ;) But these are not performance-critical functions. And by far the most inefficient part of them is that they're reading data for CPUs which cannot exist. That can be fixed with a `cpu_possible(i)' test in there, but Rusty was going to give us a `for_each_cpu' macro. We haven't seen that yet. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
| Last update: 2005-03-22 12:22 [from the cache] ©2003-2008 | |||||||||||||