Re: [PATCH] perf_counter: cleanup for __perf_event_sched_in()
From: Xiao Guangrong
Date: Tue Sep 22 2009 - 22:46:06 EST
Paul Mackerras wrote:
> Xiao Guangrong writes:
>
>> It must be a group leader if event->attr.pinned is "1"
>
> Actually, looking at this more closely, it has to be a group leader
> anyway since it's at the top level of ctx->group_list. In fact I see
> four places where we do:
>
> list_for_each_entry(event, &ctx->group_list, group_entry) {
> if (event == event->group_leader)
> ...
>
> or the equivalent, three of which appear to have been introduced by
> afedadf2 ("perf_counter: Optimize sched in/out of counters") back in
> May by Peter Z.
>
I only find three places in __perf_event_sched_in/out, could you tell me
where is the fourth place?
I also noticed that all group leader is the top level of ctx->group_list,
if I not missed, the perf_event_init_task() function can be optimized,
like this:
int perf_event_init_task(struct task_struct *child)
{
......
/* We can only look at parent_ctx->group_list to get group leader */
list_for_each_entry_rcu(event, &parent_ctx->event_list, event_entry) {
if (event != event->group_leader)
continue;
......
}
......
}
I'll fix those if you are not mind :-)
Thanks,
Xiao
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/