Subject: Re: Kernel copyin/out optimizations for ARM...
To: None <firstname.lastname@example.org>
From: David Laight <email@example.com>
Date: 03/18/2002 15:51:56
On Mon, Mar 18, 2002 at 07:29:11AM -0800, Jason R Thorpe wrote:
> On Mon, Mar 18, 2002 at 01:38:19PM +0000, Richard Earnshaw wrote:
> > As far as I could tell from some experiments I ran, the predominant use of
> > copyin/copyout was for exec().
> I benchmarked David's new version using lmbench's "bw_unix", which
> does a copyin of the data into a socket, and a copyout back out to
I wonder what size copies it is doing.
I good test would give figures for different size :-)
You could do the following peephole optimisation on the original code.
loop: ldr r3,[r0],#4
loop: subs r2,r4,#4
Which (probably) fills all the delay slots.
David Laight: firstname.lastname@example.org