Re: [xml] RAW && NXT with strncmp()

[Chris Anderson <christop charm net>]

On Wed, 2003-10-01 at 14:54, Daniel Veillard wrote:
> On Wed, Oct 01, 2003 at 02:26:30PM -0400, Chris Anderson wrote:

>   never tried icc, I believe it would generate faster code but
> my target compiler is obviously gcc :-)

Ironically, I started using icc because it works with gdb better than
g++.  icc is one cool cucumber when it comes to optimizing for x86, too
bad it's not free.


>   Well I just want the equality. One of the reasons I was using CUR/NXT
> is that I used to do some "buffer grows if needed" code handling in it.
> Not the case anymore which allows the optimisation.

Ah, that make sense.

Oops, Bjorn said he tried changing the buffer contents, I missed that.

>   Yeah it's not in hot spot (element, attributes and character parsing).
> Now if you really want to chase the microsecond, if you manage to
> optimize xmlParseCharData in parser.c, then it's an immediate gain !
> W.r.t. instruction count cachegrind was a bit surprizing initially
> finding 2000045214 cycle cost for the original and 400045209 for
> the memcmp, independantly of the string being compared. Makes some
> sense once the generated code has been looked at :-)

Yeah, I was disappointed that the compilers didn't generate int compares
instead of string compares for memcmp with a small constant size,
especially since the memories were aligned at compile time.