From: Jason Low <jason.low2@hp.com>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: peterz@infradead.org, mingo@kernel.org,
Daniel Lezcano <daniel.lezcano@linaro.org>,
riel@redhat.com, vincent.guittot@linaro.org,
srikar@linux.vnet.ibm.com, pjt@google.com,
benh@kernel.crashing.org, efault@gmx.de,
linux-kernel@vger.kernel.org, iamjoonsoo.kim@lge.com,
svaidy@linux.vnet.ibm.com, tim.c.chen@linux.intel.com,
morten.rasmussen@arm.com, jason.low2@hp.com
Subject: Re: sched: Improve load balancing in the presence of idle CPUs
Date: Tue, 31 Mar 2015 11:54:16 -0700 [thread overview]
Message-ID: <1427828056.2492.24.camel@j-VirtualBox> (raw)
In-Reply-To: <551A5CCE.70008@linux.vnet.ibm.com>
On Tue, 2015-03-31 at 14:07 +0530, Preeti U Murthy wrote:
> Hi Jason,
>
> On 03/31/2015 12:25 AM, Jason Low wrote:
> > Hi Preeti,
> >
> > I noticed that another commit 4a725627f21d converted the check in
> > nohz_kick_needed() from idle_cpu() to rq->idle_balance, causing a
> > potentially outdated value to be used if this cpu is able to pull tasks
> > using rebalance_domains(), and nohz_kick_needed() directly returning
> > false.
>
> I see that rebalance_domains() will be run at the end of the scheduler
> tick interrupt handling. trigger_load_balance() only sets the softirq,
> it does not call rebalance_domains() immediately. So the call graph
> would be:
Oh right, since that only sets the softirq, this wouldn't be the issue,
though we would need these changes if we were to incorporate any sort of
nohz_kick_needed() logic into the nohz_idle_balance() code path correct?
next prev parent reply other threads:[~2015-03-31 18:54 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-30 18:55 sched: Improve load balancing in the presence of idle CPUs Jason Low
2015-03-31 8:37 ` Preeti U Murthy
2015-03-31 18:54 ` Jason Low [this message]
2015-04-01 6:49 ` Preeti U Murthy
2015-04-01 17:04 ` Morten Rasmussen
2015-04-02 3:30 ` Jason Low
2015-04-02 8:49 ` Morten Rasmussen
2015-04-02 5:59 ` Jason Low
2015-04-02 8:42 ` Preeti U Murthy
2015-04-02 9:17 ` Morten Rasmussen
2015-04-02 17:22 ` Jason Low
2015-04-03 22:35 ` Tim Chen
2015-04-07 17:42 ` Jason Low
2015-04-07 19:39 ` Tim Chen
2015-04-07 20:24 ` Jason Low
2015-04-04 9:59 ` Preeti U Murthy
2015-04-07 23:28 ` Jason Low
2015-04-08 0:07 ` Jason Low
2015-04-08 11:12 ` Srikar Dronamraju
2015-04-08 21:22 ` Jason Low
2015-04-10 8:37 ` Srikar Dronamraju
2015-04-13 18:55 ` Jason Low
2015-04-13 20:54 ` Jason Low
2015-04-09 2:39 ` Jason Low
2015-04-09 7:02 ` Srikar Dronamraju
2015-04-09 22:49 ` Jason Low
2015-04-13 6:16 ` Preeti U Murthy
2015-04-13 22:49 ` Jason Low
2015-04-14 2:59 ` Jason Low
2015-04-02 2:11 ` Jason Low
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