From: Byungchul Park <byungchul.park@lge.com>
To: peterz@infradead.org, mingo@kernel.org
Cc: linux-kernel@vger.kernel.org, juri.lelli@gmail.com,
rostedt@goodmis.org, kernel-team@lge.com
Subject: Re: [PATCH v6 0/2] Make find_later_rq() choose a closer cpu in topology
Date: Fri, 18 Aug 2017 10:25:55 +0900 [thread overview]
Message-ID: <20170818012555.GY20323@X58A-UD3R> (raw)
In-Reply-To: <1502077834-11137-1-git-send-email-byungchul.park@lge.com>
On Mon, Aug 07, 2017 at 12:50:32PM +0900, Byungchul Park wrote:
> When cpudl_find() returns any among free_cpus, the cpu might not be
> closer than others, considering sched domain. For example:
>
> this_cpu: 15
> free_cpus: 0, 1,..., 14 (== later_mask)
> best_cpu: 0
>
> topology:
>
> 0 --+
> +--+
> 1 --+ |
> +-- ... --+
> 2 --+ | |
> +--+ |
> 3 --+ |
>
> ... ...
>
> 12 --+ |
> +--+ |
> 13 --+ | |
> +-- ... -+
> 14 --+ |
> +--+
> 15 --+
>
> In this case, it would be best to select 14 since it's a free cpu and
> closest to 15(this_cpu). However, currently the code select 0(best_cpu)
> even though that's just any among free_cpus. Fix it.
Could you let me know your opinions about this?
> Change from v5
> -. exclude two patches already picked up by peterz
> (sched/deadline: Make find_later_rq() choose a closer cpu in topology)
> (sched/deadline: Change return value of cpudl_find())
> -. apply what peterz fixed for 'prefer sibling', into deadline and rt
>
> Change from v4
> -. remove a patch that might cause huge lock contention
> (by spin lock(&cpudl.lock) in a hot path of scheduler)
>
> Change from v3
> -. rename closest_cpu to best_cpu so that it align with rt
> -. protect referring cpudl.elements with cpudl.lock
> -. change return value of cpudl_find() to bool
>
> Change from v2
> -. add support for SD_PREFER_SIBLING
>
> Change from v1
> -. clean up the patch
>
> Byungchul Park (2):
> sched/deadline: Add support for SD_PREFER_SIBLING on find_later_rq()
> sched/rt: Add support for SD_PREFER_SIBLING on find_lowest_rq()
>
> kernel/sched/deadline.c | 46 +++++++++++++++++++++++++++++++++++++++++++---
> kernel/sched/rt.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
> 2 files changed, 87 insertions(+), 6 deletions(-)
>
> --
> 1.9.1
next prev parent reply other threads:[~2017-08-18 1:26 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-07 3:50 [PATCH v6 0/2] Make find_later_rq() choose a closer cpu in topology Byungchul Park
2017-08-07 3:50 ` [PATCH v6 1/2] sched/deadline: Add support for SD_PREFER_SIBLING on find_later_rq() Byungchul Park
2017-08-15 15:19 ` Steven Rostedt
2017-08-16 0:38 ` Byungchul Park
2017-08-16 1:42 ` Steven Rostedt
2017-08-16 2:17 ` Byungchul Park
2017-08-16 13:32 ` Steven Rostedt
2017-08-16 14:04 ` Byungchul Park
2017-08-16 14:25 ` Steven Rostedt
2017-08-07 3:50 ` [PATCH v6 2/2] sched/rt: Add support for SD_PREFER_SIBLING on find_lowest_rq() Byungchul Park
2017-08-10 12:12 ` Byungchul Park
2017-08-18 1:25 ` Byungchul Park [this message]
2017-08-18 4:51 ` [PATCH v6 0/2] Make find_later_rq() choose a closer cpu in topology Joel Fernandes (Google)
2017-08-18 5:34 ` Byungchul Park
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