From: Tim Chen <tim.c.chen@linux.intel.com>
To: Shrikanth Hegde <sshegde@linux.vnet.ibm.com>
Cc: dietmar.eggemann@arm.com, vschneid@redhat.com,
linux-kernel@vger.kernel.org, srikar@linux.vnet.ibm.com,
mgorman@techsingularity.net, mingo@kernel.org,
yu.c.chen@intel.com, ricardo.neri-calderon@linux.intel.com,
iamjoonsoo.kim@lge.com, juri.lelli@redhat.com,
rocking@linux.alibaba.com, joshdon@google.com, mingo@redhat.com,
peterz@infradead.org, vincent.guittot@linaro.org
Subject: Re: [PATCH] sched/fair: optimize should_we_balance for higher SMT systems
Date: Wed, 06 Sep 2023 08:56:55 -0700 [thread overview]
Message-ID: <da676f991cd2818bcb234ac4e70c3e56c5407167.camel@linux.intel.com> (raw)
In-Reply-To: <6d958bf0-d0e9-ab6f-944f-62a123adf98d@linux.vnet.ibm.com>
On Wed, 2023-09-06 at 07:36 +0530, Shrikanth Hegde wrote:
>
> Hi Tim,
>
> Thanks for taking a look at this patch.
>
> > Wonder if we can avoid allocating the
> > should_we_balance_tmpmask for SMT2 case to save memory
> > for system with large number of cores.
> >
> > The new mask and logic I think is only needed for more than 2 threads in a core.
>
> Code would have to be refactored quite a bit if one needs to take
> different approach for specific SMT setting.
>
> I think there would some cases in SMT2 that will benefit as well.
> Lets say 1 cpu in each core is busy. the busy CPU happens to be second
> CPU in the core. In that case, this approach would skip that instead of
> checking if that is idle or not.
>
>
That's true. This change could skip the sibling for SMT2.
Tim
prev parent reply other threads:[~2023-09-06 15:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-02 8:12 [PATCH] sched/fair: optimize should_we_balance for higher SMT systems Shrikanth Hegde
2023-09-02 10:58 ` Ingo Molnar
2023-09-06 1:48 ` Shrikanth Hegde
2023-09-02 16:17 ` [tip: sched/urgent] sched/fair: Optimize should_we_balance() for large " tip-bot2 for Shrikanth Hegde
2023-09-05 19:30 ` [PATCH] sched/fair: optimize should_we_balance for higher " Tim Chen
2023-09-06 2:06 ` Shrikanth Hegde
2023-09-06 15:56 ` Tim Chen [this message]
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