linux-kernel - Re: [PATCH v3 -tip] sched: Clean unused fields from struct rq

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Date:	Thu, 19 Mar 2009 08:49:49 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Luis Henriques <henrix@...o.pt>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Gregory Haskins <ghaskins@...ell.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 -tip] sched: Clean unused fields from struct rq


* Luis Henriques <henrix@...o.pt> wrote:

> On Wed, Mar 18, 2009 at 10:51:37PM +0000, Luis Henriques wrote:
> > Since they are used on in statistics and are always set to zero, the following
> > fields from struct rq have been removed: yld_exp_empty, yld_act_empty and
> > yld_both_empty.
> > 
> > Both Sched Debug and SCHEDSTAT_VERSION versions has also been incremented since
> > ABIs have been changed.
> > 
> > Signed-off-by: Luis Henriques <henrix@...o.pt>
> > ---
> >  kernel/sched.c       |    3 ---
> >  kernel/sched_debug.c |    5 +----
> >  kernel/sched_stats.h |    7 +++----
> >  3 files changed, 4 insertions(+), 11 deletions(-)
> > 
> > diff --git a/kernel/sched.c b/kernel/sched.c
> > index 8a579e2..4469034 100644
> > --- a/kernel/sched.c
> > +++ b/kernel/sched.c
> > @@ -646,9 +646,6 @@ struct rq {
> >  	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
> >  
> >  	/* sys_sched_yield() stats */
> > -	unsigned int yld_exp_empty;
> > -	unsigned int yld_act_empty;
> > -	unsigned int yld_both_empty;
> >  	unsigned int yld_count;
> >  
> >  	/* schedule() stats */
> > diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
> > index 4daebff..467ca72 100644
> > --- a/kernel/sched_debug.c
> > +++ b/kernel/sched_debug.c
> > @@ -286,9 +286,6 @@ static void print_cpu(struct seq_file *m, int cpu)
> >  #ifdef CONFIG_SCHEDSTATS
> >  #define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, rq->n);
> >  
> > -	P(yld_exp_empty);
> > -	P(yld_act_empty);
> > -	P(yld_both_empty);
> >  	P(yld_count);
> >  
> >  	P(sched_switch);
> > @@ -313,7 +310,7 @@ static int sched_debug_show(struct seq_file *m, void *v)
> >  	u64 now = ktime_to_ns(ktime_get());
> >  	int cpu;
> >  
> > -	SEQ_printf(m, "Sched Debug Version: v0.08, %s %.*s\n",
> > +	SEQ_printf(m, "Sched Debug Version: v0.09, %s %.*s\n",
> >  		init_utsname()->release,
> >  		(int)strcspn(init_utsname()->version, " "),
> >  		init_utsname()->version);
> > diff --git a/kernel/sched_stats.h b/kernel/sched_stats.h
> > index a8f93dd..32d2bd4 100644
> > --- a/kernel/sched_stats.h
> > +++ b/kernel/sched_stats.h
> > @@ -4,7 +4,7 @@
> >   * bump this up when changing the output format or the meaning of an existing
> >   * format, so that tools can adapt (or abort)
> >   */
> > -#define SCHEDSTAT_VERSION 14
> > +#define SCHEDSTAT_VERSION 15
> >  
> >  static int show_schedstat(struct seq_file *seq, void *v)
> >  {
> > @@ -26,9 +26,8 @@ static int show_schedstat(struct seq_file *seq, void *v)
> >  
> >  		/* runqueue-specific stats */
> >  		seq_printf(seq,
> > -		    "cpu%d %u %u %u %u %u %u %u %u %u %llu %llu %lu",
> > -		    cpu, rq->yld_both_empty,
> > -		    rq->yld_act_empty, rq->yld_exp_empty, rq->yld_count,
> > +		    "cpu%d %u %u %u %u %u %u %llu %llu %lu",
> > +		    cpu, rq->yld_count,
> >  		    rq->sched_switch, rq->sched_count, rq->sched_goidle,
> >  		    rq->ttwu_count, rq->ttwu_local,
> >  		    rq->rq_cpu_time,
> > -- 
> > 1.6.2
> 
> Btw: I tried Greg schedtop with this patch and the app behaviour is as expected:
> 
>   $ ./schedtop 
>   Exception: unsupported version

Mind updating the app too and post it here please? It's the only app 
that relies on this file AFAIK.

	Ingo
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