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From: Qais Yousef <qais.yousef@arm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Pavan Kondeti <pkondeti@codeaurora.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] sched/rt: cpupri_find: implement fallback mechanism for !fit case
Date: Tue, 18 Feb 2020 18:52:54 +0000	[thread overview]
Message-ID: <20200218185253.yryfozr7jf2ve4lv@e107158-lin> (raw)
In-Reply-To: <20200218130300.679f77ea@gandalf.local.home>

On 02/18/20 13:03, Steven Rostedt wrote:
> On Tue, 18 Feb 2020 17:27:46 +0000
> Qais Yousef <qais.yousef@arm.com> wrote:
> 
> > > If we are going to use static branches, then lets just remove the
> > > parameter totally. That is, make two functions (with helpers), where
> > > one needs this fitness function the other does not.
> > > 
> > > 	if (static_branch_unlikely(&sched_asym_cpu_capacity))
> > > 		ret = cpupri_find_fitness(...);
> > > 	else
> > > 		ret = cpupri_find(...);
> > > 
> > > 	if (!ret)
> > > 		return -1;
> > > 
> > > Something like that?  
> > 
> > Is there any implication on code generation here?
> > 
> > I like my flavour better tbh. But I don't mind refactoring the function out if
> > it does make it more readable.
> 
> I just figured we remove the passing of the parameter (which does make
> an impact on the code generation).

Ok. My mind went to protecting the whole function call with the static key
could be better.

> Also, perhaps it would be better to not have to pass functions to the
> cpupri_find(). Is there any other function that needs to be past, or
> just this one in this series?

I had that discussion in the past with Dietmar [1]

My argument was this way the code is generic and self contained and allows for
easy extension for other potential users.

I'm happy to split the function into cpupri_find_fitness() (with a fn ptr) and
cpupri_find() (original) like you suggest above - if you're still okay with
that..

[1] https://lore.kernel.org/lkml/39c08971-5d07-8018-915b-9c6284f89d5d@arm.com/

Thanks

--
Qais Youesf

  reply	other threads:[~2020-02-18 18:53 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14 16:39 [PATCH 0/3] RT Capacity Awareness Improvements Qais Yousef
2020-02-14 16:39 ` [PATCH 1/3] sched/rt: cpupri_find: implement fallback mechanism for !fit case Qais Yousef
2020-02-17 17:07   ` Valentin Schneider
2020-02-17 23:34     ` Qais Yousef
2020-02-18 10:01       ` Valentin Schneider
2020-02-17 19:09   ` Dietmar Eggemann
2020-02-17 23:45     ` Qais Yousef
2020-02-18  9:53       ` Dietmar Eggemann
2020-02-18 17:28         ` Qais Yousef
2020-02-18 16:46       ` Steven Rostedt
2020-02-18 17:27         ` Qais Yousef
2020-02-18 18:03           ` Steven Rostedt
2020-02-18 18:52             ` Qais Yousef [this message]
2020-02-14 16:39 ` [PATCH 2/3] sched/rt: allow pulling unfitting task Qais Yousef
2020-02-17  9:10   ` Pavan Kondeti
2020-02-17 11:20     ` Qais Yousef
2020-02-19 13:43     ` Qais Yousef
2020-02-21  8:07       ` Pavan Kondeti
2020-02-21 11:08         ` Qais Yousef
2020-02-14 16:39 ` [PATCH 3/3] sched/rt: fix pushing unfit tasks to a better CPU Qais Yousef
2020-02-17  9:23   ` Pavan Kondeti
2020-02-17 13:53     ` Qais Yousef
2020-02-18  4:16       ` Pavan Kondeti
2020-02-18 17:47         ` Qais Yousef
2020-02-19  2:46           ` Pavan Kondeti
2020-02-19 10:46             ` Qais Yousef
2020-02-19 14:02       ` Qais Yousef
2020-02-21  8:15         ` Pavan Kondeti
2020-02-21 11:12           ` Qais Yousef

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