From: Peter Zijlstra <peterz@infradead.org>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
morten.rasmussen@arm.com
Subject: Re: [PATCH v3 7/7] sched/topology: Use prebuilt SD flag degeneration mask
Date: Mon, 13 Jul 2020 14:55:43 +0200 [thread overview]
Message-ID: <20200713125543.GJ10769@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200701190656.10126-8-valentin.schneider@arm.com>
On Wed, Jul 01, 2020 at 08:06:55PM +0100, Valentin Schneider wrote:
> Leverage SD_DEGENERATE_GROUPS_MASK in sd_degenerate() and
> sd_degenerate_parent().
>
> Note that this changes sd_degenerate() somewhat: I'm using the negation of
> SD_DEGENERATE_GROUPS_MASK as the mask of flags not requiring groups, which
> is equivalent to:
>
> SD_WAKE_AFFINE | SD_SERIALIZE | SD_NUMA
>
> whereas the current mask for that is simply
>
> SD_WAKE_AFFINE
>
> I played with a few toy NUMA topologies on QEMU and couldn't cause a
> different degeneration than what mainline does currently. If that is deemed
> too risky, we can go back to using SD_WAKE_AFFINE explicitly.
Arguably SD_SERIALIZE needs groups, note how we're only having that
effective for machines with at least 2 nodes. It's a bit shit how we end
up there, but IIRC that's what it ends up as.
SD_NUMA is descriptive, and not marking a group as degenerates because
it has SD_NUMA seems a bit silly. But then, it would be the top domain
and would survive anyway?
next prev parent reply other threads:[~2020-07-13 12:55 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-01 19:06 [PATCH v3 0/7] sched: Instrument sched domain flags Valentin Schneider
2020-07-01 19:06 ` [PATCH v3 1/7] sched/topology: Split out SD_* flags declaration to its own file Valentin Schneider
2020-07-01 19:06 ` [PATCH v3 2/7] sched/topology: Define and assign sched_domain flag metadata Valentin Schneider
2020-07-02 12:15 ` Quentin Perret
2020-07-02 14:31 ` Valentin Schneider
2020-07-02 15:45 ` Quentin Perret
2020-07-02 16:25 ` Valentin Schneider
2020-07-02 16:37 ` Quentin Perret
2020-07-02 16:49 ` Valentin Schneider
2020-07-01 19:06 ` [PATCH v3 3/7] sched/topology: Verify SD_* flags setup when sched_debug is on Valentin Schneider
2020-07-02 14:20 ` Peter Zijlstra
2020-07-02 14:32 ` Valentin Schneider
2020-07-01 19:06 ` [PATCH v3 4/7] arm, sched/topology: Remove SD_SHARE_POWERDOMAIN Valentin Schneider
2020-07-02 16:44 ` Dietmar Eggemann
2020-07-02 18:46 ` Valentin Schneider
2020-07-01 19:06 ` [PATCH v3 5/7] sched/topology: Add more flags to the SD degeneration mask Valentin Schneider
2020-07-02 18:28 ` Dietmar Eggemann
2020-07-01 19:06 ` [PATCH v3 6/7] sched/topology: Introduce SD metaflag for flags needing > 1 groups Valentin Schneider
2020-07-02 18:29 ` Dietmar Eggemann
2020-07-02 18:46 ` Valentin Schneider
2020-07-13 12:39 ` Peter Zijlstra
2020-07-13 13:25 ` Valentin Schneider
2020-07-01 19:06 ` [PATCH v3 7/7] sched/topology: Use prebuilt SD flag degeneration mask Valentin Schneider
2020-07-13 12:55 ` Peter Zijlstra [this message]
2020-07-13 13:28 ` Valentin Schneider
2020-07-13 13:43 ` Peter Zijlstra
2020-07-13 13:52 ` Valentin Schneider
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