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From: Frederic Weisbecker <fweisbec@gmail.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>,
	Anton Blanchard <anton@au1.ibm.com>,
	linux-kernel@vger.kernel.org, paulus@samba.org,
	paulmck@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC PATCH v3 0/5] powerpc: Support context tracking for Power pSeries
Date: Wed, 29 May 2013 23:32:01 +0200	[thread overview]
Message-ID: <20130529213159.GD17419@somewhere> (raw)
In-Reply-To: <1368435563.19924.28.camel@pasglop>

On Mon, May 13, 2013 at 06:59:23PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2013-05-13 at 16:03 +0800, Li Zhong wrote:
> > 
> > To my understanding, it is used to enable RCU user extended quiescent
> > state, so RCU on that cpu doesn't need scheduler ticks. And together
> > with some other code(already in 3.10), we are able to remove the ticks
> > in some cases (e.g. only 1 task running on the cpu, with some other
> > limitations).
> 
> Ok, sounds interesting. Once you fix the little cosmetic issue, I don't
> see any reason not to merge them as it's basically wiring up an existing
> feature (in that regard the patches are pretty straightforward) and I
> assume the overhead is only there when you enable it.

Yeah when CONFIG_RCU_USER_QS=n and CONFIG_VIRT_CPU_ACCOUNTING_GEN=n this
should be zero overhead. And those configs are only needed for full dynticks.

Thanks.

> 
> Cheers,
> Ben.
> 
> 

  parent reply	other threads:[~2013-05-29 21:32 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-13  5:21 [RFC PATCH v3 0/5] powerpc: Support context tracking for Power pSeries Li Zhong
2013-05-13  5:21 ` [RFC PATCH v3 1/5] powerpc: Syscall hooks for context tracking subsystem Li Zhong
2013-05-13  5:21 ` [RFC PATCH v3 2/5] powerpc: Exception " Li Zhong
2013-05-13  5:57   ` Benjamin Herrenschmidt
2013-05-13  8:44     ` Li Zhong
2013-05-13  9:06       ` Benjamin Herrenschmidt
2013-05-13  9:46         ` Li Zhong
2013-05-13 10:01           ` Benjamin Herrenschmidt
2013-05-13  5:21 ` [RFC PATCH v3 3/5] powerpc: Exit user context on notify resume Li Zhong
2013-05-13  5:21 ` [RFC PATCH v3 4/5] powerpc: Use the new schedule_user API on userspace preemption Li Zhong
2013-05-13  5:21 ` [RFC PATCH v3 5/5] powerpc: select HAVE_CONTEXT_TRACKING for pSeries Li Zhong
2013-05-13  5:51 ` [RFC PATCH v3 0/5] powerpc: Support context tracking for Power pSeries Benjamin Herrenschmidt
2013-05-13  8:03   ` Li Zhong
2013-05-13  8:59     ` Benjamin Herrenschmidt
2013-05-13  9:22       ` Li Zhong
2013-05-29 21:32       ` Frederic Weisbecker [this message]
2013-05-29 21:29     ` Frederic Weisbecker

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