Re: [xml] xmlDocDumpMemory() is VERY slow on Win32

[Jose Commins <axora myrealbox com>]

        On MacOSX 10.3.4, 650Mhz G4 Mac (100Mhz system bus):

        gcc -o steve2 steve2.c
        time ./steve2.c

malloc OK (16000)
000: realloc OK (16000 to 32000)
001: realloc OK (32000 to 48000)
002: realloc OK (48000 to 64000)
003: realloc OK (64000 to 80000)
004: realloc OK (80000 to 96000)
<blah>
637: realloc OK (10208000 to 10224000)
638: realloc OK (10224000 to 10240000)
639: realloc OK (10240000 to 10256000)
1 seconds
0.000u 0.020s 0:00.72 2.7%      0+0k 0+0io 0pf+0w


	It would be interesting to compare in Windows both Athlon versus Intel 
chips, as Athlons for example have a different virtual memory paging 
implementation.


Regards,
                Jose.

--
Arguing with an engineer is like wrestling with a pig in mud.
After a while, you realize the pig is enjoying it.


On 13 Jul 2004, at 16:37, Steve Hay wrote:

> OK.  So the first sequence in which the buffer is being doubled is the
> xmlReadFile() call, reading in the 10MB file.  The second sequence in
> which the buffer is grown by 16000 bytes at a time is what Igor 
> referred
> to -- and it is indeed approx 640 calls (10MB / 16000bytes) as he 
> predicted.
>
> I now share Igor's bad feeling about this in the light of the following
> program:
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <malloc.h>
> #include <time.h>
> void main(void) {
>   char *buf;
>   int i, size;
>   time_t start, end;
>   size = 16000;
>   if ((buf = malloc(size)) == NULL) {
>     printf("malloc failed\n");
>     exit(3);
>   }
>   else {
>     printf("malloc OK (%d)\n", size);
>   }
>   time(&start);
>   for (i = 0; i < 640; i++, size += 16000) {
>     if ((buf = (char *)realloc(buf, size + 16000)) == NULL) {
>       printf("%03d: realloc failed\n", i);
>       exit(4);
>     }
>     else {
>       printf("%03d: realloc OK (%d to %d)\n", i, size, size + 16000);
>     }
>   }
>   time(&end);
>   free(buf);
>   printf("%d seconds\n", end - start);
>   exit(0);
> }
>
> Could somebody please try this on Linux (well, anything other than 
> Win32
> I guess) and tell me how long it takes to run?
>
> On my P4 2GHz Win32 box it takes 15seconds -- exactly the same time as
> the XML parsing/dumping earlier!  (And it's just as slow without the
> printf() calls in it.)
>
> I dare say the time will be 0 or 1 second on Linux.
>
> My soul is indeed lost :(  Where do I go from here?  (Don't say 
> Linux...)
>
> - Steve