linux-kernel - Re: [PATCH 2/3] cputime: Rename thread_group_times to thread_group_cputime

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Message-ID: <CAFTL4hxxE8Ggw4Ae-VfgBZ8rtoOMpUQnmSGUado1gxeruwQ9rg@mail.gmail.com>
Date:	Mon, 26 Nov 2012 20:24:09 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 2/3] cputime: Rename thread_group_times to thread_group_cputime_adjusted

2012/11/26 Steven Rostedt <rostedt@...dmis.org>:
> On Fri, 2012-11-23 at 15:21 +0100, Frederic Weisbecker wrote:
>> We have thread_group_cputime() and thread_group_times(). The naming
>> doesn't provide enough information about the difference between
>> these two APIs.
>>
>> To lower the confusion, rename thread_group_times() to
>> thread_group_cputime_adjusted(). This name better suggests that
>> it's a version of thread_group_cputime() that does some stabilization
>> on the raw cputime values. ie here: scale on top of CFS runtime
>> stats and bound lower value for monotonicity.
>
> But, thread_group_times() does not do any type of adjustment. It only
> retrieves the cpu times:
>
> void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
> {
>         struct task_cputime cputime;
>
>         thread_group_cputime(p, &cputime);
>
>         *ut = cputime.utime;
>         *st = cputime.stime;
> }

This is the CONFIG_VIRT_CPU_ACCOUNTING only version. It also needs
some monotonicity guard IMO but that's another issue.
But please look at the other version.

> It retrieves the current times, it doesn't adjust them.
>
> I'm thinking the current name is more accurate.
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