linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Valentin Schneider <valentin.schneider@arm.com>
To: Steve Sistare <steven.sistare@oracle.com>,
	mingo@redhat.com, peterz@infradead.org
Cc: subhra.mazumdar@oracle.com, dhaval.giani@oracle.com,
	daniel.m.jordan@oracle.com, pavel.tatashin@microsoft.com,
	matt@codeblueprint.co.uk, umgwanakikbuti@gmail.com,
	riel@redhat.com, jbacik@fb.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, quentin.perret@arm.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 05/10] sched/fair: Hoist idle_stamp up from idle_balance
Date: Fri, 9 Nov 2018 19:07:58 +0000	[thread overview]
Message-ID: <9ad62a6f-0269-a5d9-9757-ba5419f9cc1d@arm.com> (raw)
In-Reply-To: <1541767840-93588-6-git-send-email-steven.sistare@oracle.com>

Hi Steve,

On 09/11/2018 12:50, Steve Sistare wrote:
> Move the update of idle_stamp from idle_balance to the call site in
> pick_next_task_fair, to prepare for a future patch that adds work to
> pick_next_task_fair which must be included in the idle_stamp interval.
> No functional change.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>  kernel/sched/fair.c | 23 ++++++++++++++---------
>  1 file changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 9031d39..da368ed 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3725,6 +3725,8 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq)
>  	rq->misfit_task_load = task_h_load(p);
>  }
>  
> +#define IF_SMP(statement)	statement
> +

I'm not too hot on those IF_SMP() macros. Since you're not introducing
any other user for them, what about an inline function for rq->idle_stamp
setting ? When it's mapped to an empty statement (!CONFIG_SMP) GCC is
smart enough to remove the rq_clock() that would be passed to it on
CONFIG_SMP:

----->8-----

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c11adf3..34d9864 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3725,7 +3725,10 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq)
        rq->misfit_task_load = task_h_load(p);
 }
 
-#define IF_SMP(statement)      statement
+static inline void set_rq_idle_stamp(struct rq *rq, u64 value)
+{
+       rq->idle_stamp = value;
+}
 
 static void overload_clear(struct rq *rq)
 {
@@ -3772,7 +3775,7 @@ static inline int idle_balance(struct rq *rq, struct rq_flags *rf)
        return 0;
 }
 
-#define IF_SMP(statement)      /* empty */
+static inline void set_rq_idle_stamp(struct rq *rq, u64 value) {}
 
 static inline void overload_clear(struct rq *rq) {}
 static inline void overload_set(struct rq *rq) {}
@@ -6773,12 +6776,12 @@ done: __maybe_unused;
         * We must set idle_stamp _before_ calling idle_balance(), such that we
         * measure the duration of idle_balance() as idle time.
         */
-       IF_SMP(rq->idle_stamp = rq_clock(rq);)
+       set_rq_idle_stamp(rq, rq_clock(rq));
 
        new_tasks = idle_balance(rq, rf);
 
        if (new_tasks)
-               IF_SMP(rq->idle_stamp = 0;)
+               set_rq_idle_stamp(rq, 0);
 
        /*
         * Because idle_balance() releases (and re-acquires) rq->lock, it is

  reply	other threads:[~2018-11-09 19:08 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-09 12:50 [PATCH v3 00/10] steal tasks to improve CPU utilization Steve Sistare
2018-11-09 12:50 ` [PATCH v3 01/10] sched: Provide sparsemask, a reduced contention bitmap Steve Sistare
2018-11-27 15:16   ` Steven Sistare
2018-11-28  1:19     ` Omar Sandoval
2018-12-06 16:07       ` Steven Sistare
2018-12-06 18:19         ` Omar Sandoval
2018-11-09 12:50 ` [PATCH v3 02/10] sched/topology: Provide hooks to allocate data shared per LLC Steve Sistare
2018-11-09 12:50 ` [PATCH v3 03/10] sched/topology: Provide cfs_overload_cpus bitmap Steve Sistare
2018-11-09 17:38   ` Valentin Schneider
2018-11-19 17:32     ` Steven Sistare
2018-11-20 12:52       ` Valentin Schneider
2018-11-12 16:42   ` Valentin Schneider
2018-11-19 17:33     ` Steven Sistare
2018-11-20 12:42       ` Valentin Schneider
2018-11-26 19:06         ` Steven Sistare
2018-12-03 16:56           ` Valentin Schneider
2018-12-06 16:40             ` Steven Sistare
2018-12-06 17:28               ` Valentin Schneider
2018-11-09 12:50 ` [PATCH v3 04/10] sched/fair: Dynamically update cfs_overload_cpus Steve Sistare
2018-11-09 12:50 ` [PATCH v3 05/10] sched/fair: Hoist idle_stamp up from idle_balance Steve Sistare
2018-11-09 19:07   ` Valentin Schneider [this message]
2018-11-19 17:31     ` Steven Sistare
2018-11-20 10:24       ` Valentin Schneider
2018-11-09 12:50 ` [PATCH v3 06/10] sched/fair: Generalize the detach_task interface Steve Sistare
2018-11-09 12:50 ` [PATCH v3 07/10] sched/fair: Provide can_migrate_task_llc Steve Sistare
2018-11-09 12:50 ` [PATCH v3 08/10] sched/fair: Steal work from an overloaded CPU when CPU goes idle Steve Sistare
2018-11-09 12:50 ` [PATCH v3 09/10] sched/fair: disable stealing if too many NUMA nodes Steve Sistare
2018-11-09 12:50 ` [PATCH v3 10/10] sched/fair: Provide idle search schedstats Steve Sistare
2018-11-10 17:08   ` kbuild test robot
2018-11-09 15:02 ` hackbench run scripts Steven Sistare

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=9ad62a6f-0269-a5d9-9757-ba5419f9cc1d@arm.com \
    --to=valentin.schneider@arm.com \
    --cc=daniel.m.jordan@oracle.com \
    --cc=dhaval.giani@oracle.com \
    --cc=jbacik@fb.com \
    --cc=juri.lelli@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=matt@codeblueprint.co.uk \
    --cc=mingo@redhat.com \
    --cc=pavel.tatashin@microsoft.com \
    --cc=peterz@infradead.org \
    --cc=quentin.perret@arm.com \
    --cc=riel@redhat.com \
    --cc=steven.sistare@oracle.com \
    --cc=subhra.mazumdar@oracle.com \
    --cc=umgwanakikbuti@gmail.com \
    --cc=vincent.guittot@linaro.org \
    --subject='Re: [PATCH v3 05/10] sched/fair: Hoist idle_stamp up from idle_balance' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).