Re: [PATCH] Optimize sys_times for a single thread process

[Mitchell Blank Jr <mitch@sfgoth.com>]

Christoph Lameter wrote:
> +		if (current == next_thread(current)) {
> +			/*
> +			 * Single thread case. We do not need to scan the tasklist
> +			 * and thus can avoid the read_lock(&task_list_lock). We
> +			 * also do not need to take the siglock since we
> +			 * are the only thread in this process
> +			 */
> +			utime = cputime_add(current->signal->utime, current->utime);
> +			stime = cputime_add(current->signal->utime, current->stime);
> +			cutime = current->signal->cutime;
> +			cstime = current->signal->cstime;
> +		} else

Maybe #ifdef CONFIG_SMP around this?  On uniproc you're still saving the
sti/cli around reading the tsk->signal stuff but that's probably not
enough to warrant the code bloat.

Or maybe this is a small enough amount of code not to matter... just a
suggestion.

-Mitch