linux-kernel - Re: [PATCH] Fake NUMA emulation for PowerPC

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Date:	Sat, 08 Dec 2007 03:33:09 +0530
From:	Balbir Singh <balbir@...ux.vnet.ibm.com>
To:	Arnd Bergmann <arnd@...db.de>
CC:	linuxppc-dev@...abs.org,
	Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Fake NUMA emulation for PowerPC

Arnd Bergmann wrote:
> On Friday 07 December 2007, Balbir Singh wrote:
>> Balbir Singh wrote:
>>> Geert Uytterhoeven wrote:
>>>> On Sat, 8 Dec 2007, Balbir Singh wrote:
>>>>> +   if (strstr(p, "fake="))
>>>>> +           cmdline = p + 5;        /* 5 is faster than strlen("fake=") */
>>>> Really? My gcc is smart enough to replace the `strlen("fake=")' by 5, even
>>>> without -O.
>>>>
>>> Thanks for pointing that out, but I am surprised that a compiler would
>>> interpret library routines like strlen.
>>>
>> I just tested it and it turns out that you are right. I'll go hunt to
>> see where gcc gets its magic powers from.
>>
> 
> Even if it wasn't: Why the heck would you want to optimize this? The function
> is run _once_ at boot time and the object code gets thrown away afterwards!
> 
> 	Arnd <><

Cause, I see no downside of doing it. The strlen of fake= is fixed.
But having said that, I am not a purist about the approach, I just want
cmdline to point after "fake="

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
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