From: Ralf Baechle <ralf@linux-mips.org>
To: Tinga Shilo <tingashilo@yahoo.com>
Cc: linux-mips@linux-mips.org
Subject: Re: static variables access and gp
Date: Sun, 9 Mar 2003 14:46:26 +0100 [thread overview]
Message-ID: <20030309144625.A27651@linux-mips.org> (raw)
In-Reply-To: <20030306073017.65521.qmail@web41509.mail.yahoo.com>; from tingashilo@yahoo.com on Wed, Mar 05, 2003 at 11:30:17PM -0800
On Wed, Mar 05, 2003 at 11:30:17PM -0800, Tinga Shilo wrote:
> I am implementing a kernel mechanism which is
> very performance oriented. Along my long critical
> path,
> there is a static variable that needs to be accessed
> quite a few times. This variable is a structure which
> is approximately 60 bytes big.
> In there any way I can "convince" my kernel (compiled
> with gcc) to access this variable using gp ?
> Is gp usually used for this purpose in mips-linux ?
> Can it be ?
>
> A while ago I saw a small discussion here about usage
> of gp for static variables, but it didn't provide
> any definite answers.
Use a pointer to the that structure. Gcc will keep this pointer in a
registers wherever it considers that sensible. Any reference to members
of the structure can then be made with just a single instruction.
$28 is used for the current pointer so only suitable for per-process
data.
Ralf
prev parent reply other threads:[~2003-03-09 13:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-06 7:30 static variables access and gp Tinga Shilo
2003-03-06 17:40 ` Jun Sun
2003-03-09 7:24 ` Tinga Shilo
2003-03-09 7:24 ` Tinga Shilo
2003-03-09 13:46 ` Ralf Baechle [this message]
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