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From: Maksym Planeta <mcsim.planeta@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: tglx@linutronix.de, kernel-janitors@vger.kernel.org,
	mingo@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: page: get_order() optimization
Date: Sun, 27 Mar 2011 11:57:59 +0300	[thread overview]
Message-ID: <1301216279.15393.9.camel@debian> (raw)
In-Reply-To: <20110323100757.GA14245@elte.hu>

On Wed, 23/03/2011 at 11:07 +0100, Ingo Molnar wrote:

> Ok, that's certainly a nice optimization.

Thanks, I rewrote patch according to your observations.

> One detail: in many cases 'size' is a constant. Have you checked recent GCC, 
> does it turn the generic version of get_order() into a loop even for constants, 
> or is it able does it perhaps recognize the pattern and precompute the result?

Yes, gcc precomputes the result, so I added case for constants.

> With no #ifdefs in get_order().

And removed #ifdefs from get_order().

-- 
Thanks,

Maksym Planeta


  reply	other threads:[~2011-03-27  8:56 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-19 16:25 [PATCH] x86: page: get_order() optimization Maksym Planeta
2011-03-23 10:07 ` Ingo Molnar
2011-03-27  8:57   ` Maksym Planeta [this message]
  -- strict thread matches above, loose matches on Subject: below --
2011-03-19 16:08 Maksym Planeta

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