ZLIB 1.2.1 - excessive page faults? Bug? Strange...!

Hi there

See the following small test program:

-------------------
unsigned char src[10000];
unsigned char dst[10500];
unsigned long dstlen = 10500;
while (1)
{
long r = compress2( (unsigned char*)dst,    // dst
&dstlen,        // compressed len
src,    // memory to compress
8192,     // src len
9);          // compression level
Sleep(2);
}
------------------

I use WindowsXP. The compiler is MetroWerks CodeWarrior 9.2

I get a large number of page faults in my program.
TaskManager says 20.000/s. This is a problem, since
we are creating a large application with 10.000 connections
at the same time, and use the zlib to compress the traffic.
But with so many page faults the program runs slow.

I have no idea whats going on, even trying to looks around
alot in your code.

Why would the compressor generate page faults...???

sincerely
Søren

"PokerAddict" <sodan@NOSPAMsodan.dk> wrote in message news:
> Why would the compressor generate page faults...???

There is apparently very little real memory available to that task.
zlib uses on the order of 256K bytes as a hash table, with essentially
shotgun reads and writes.  So somehow your task is getting less than
256K of real memory (on a modern machine with a few orders of
magnitude more memory?).

mark

PokerAddict wrote:
> Hi there
>
> See the following small test program:
>
> -------------------
>  unsigned char src[10000];
>  unsigned char dst[10500];
>  unsigned long dstlen = 10500;
>  while (1)
>  {
>   long r = compress2( (unsigned char*)dst,    // dst
>        &dstlen,        // compressed len
>        src,    // memory to compress
>        8192,     // src len
>        9);          // compression level
>   Sleep(2);
>  }
> ------------------
>
> I use WindowsXP. The compiler is MetroWerks CodeWarrior 9.2
>
> I get a large number of page faults in my program.
> TaskManager says 20.000/s. This is a problem, since
> we are creating a large application with 10.000 connections
> at the same time, and use the zlib to compress the traffic.
> But with so many page faults the program runs slow.
>
> I have no idea whats going on, even trying to looks around
> alot in your code.
>
> Why would the compressor generate page faults...???

it may have nothing to do with this.  Might it be
a dynamic linking problem?  Can you link in the compressor
library statically?

>
> sincerely
> Søren
>
>