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Date: Thu, 13 Apr 2017 17:05:13 +0530
From: Gautham R Shenoy <ego@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>,
 "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
 "Shreyas B. Prabhu" <shreyasbp@gmail.com>,
 Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>,
 Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
 Anton Blanchard <anton@samba.org>, Balbir Singh <bsingharora@gmail.com>,
 Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>,
 Nicholas Piggin <npiggin@gmail.com>,
 Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>,
 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
 linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] powernv:idle: Use correct IDLE_THREAD_BITS in POWER8/9
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On Thu, Apr 13, 2017 at 08:00:47PM +1000, Michael Ellerman wrote:
> Michael Neuling <mikey@neuling.org> writes:
> 
> > On Wed, 2017-04-12 at 17:16 +0530, Gautham R. Shenoy wrote:
> >> From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
> >> 
> >> This patch ensures that POWER8 and POWER9 processors use the correct
> >> value of IDLE_THREAD_BITS as POWER8 has 8 threads per core and hence
> >> the IDLE_THREAD_BITS should be 0xFF while POWER9 has only 4 threads
> >> per core and hence the IDLE_THREAD_BITS should be 0xF.
> >
> > Why don't we derive this from the device tree rather than hard wiring it per cpu
> > type?
> 
> Right.
> 
> In fact we already have threads_per_core which is exactly that.

Ok. I will convert IDLE_THREAD_BITS to a variable instead of a
macro so that the variable holds the value
(1 << threads_per_core) - 1.



> 
> cheers
>