From: "Jan Beulich" <jbeulich@novell.com>
To: <hpa@zytor.com>
Cc: <mingo@elte.hu>, <tglx@linutronix.de>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86: introduce and use percpu_inc()
Date: Thu, 22 Apr 2010 07:26:19 +0100 [thread overview]
Message-ID: <4BCFFA1B020000780005CBAE@vpn.id2.novell.com> (raw)
>>> "H. Peter Anvin" 04/21/10 7:57 PM >>>
>On 04/21/2010 07:21 AM, Jan Beulich wrote:
>> ... generating slightly smaller code.
>>
>> Signed-off-by: Jan Beulich
>
>How much smaller?
The percpu_add(..., 1) -> percpu_inc() conversion is just a single
byte reduction (the immediate operand of the add); the other one
(where percpu_...() wasn't even used) is certainly a bigger win
(most of which obviously could also be achieved using percpu_add()).
>Keep in mind that although INC is smaller than ADD,
>the former has flag dependencies that the latter doesn't...
Wasn't that a problem just on Pentium4-s, which when I submitted
another related patch a couple of months back I was told would
not be a primary target anymore?
Jan
next reply other threads:[~2010-04-22 6:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-22 6:26 Jan Beulich [this message]
2010-04-22 6:48 ` H. Peter Anvin
2010-04-22 11:01 ` Jan Beulich
-- strict thread matches above, loose matches on Subject: below --
2010-04-21 14:21 Jan Beulich
2010-04-21 17:56 ` H. Peter Anvin
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