I have attached a question concerning using 4GB of memory on an SMP.
Thanks for the time,
Dave
SMP Not using all 4GB Ram Question:
---------------------------------------------------------------------
I am using a Compaq Proliant 8500 SMP with 8 550 Mhz processors and 4GB of RAM.
Using Kernel 2.4.3 and Redhat 6.2
I have the (4GB) High Memory Support enabled.
I seem not to be able to use more that 1GB of memory.
The Following is my /proc/meminfo file
----------------------------------------------------------------------
total: used: free: shared: buffers: cached:
Mem: 3952427008 339447808 3612979200 0 256139264 25030656
Swap: 1048633344 0 1048633344
MemTotal: 3859792 kB
MemFree: 3528300 kB
MemShared: 0 kB
Buffers: 250136 kB
Cached: 24444 kB
Active: 16628 kB
Inact_dirty: 257952 kB
Inact_clean: 0 kB
Inact_target: 172 kB
HighTotal: 3014624 kB
HighFree: 2978372 kB
LowTotal: 845168 kB
LowFree: 549928 kB
SwapTotal: 1024056 kB
SwapFree: 1024056 kB
--------------------------------------------------------------
I wrote the following program that simply allocates 100M of memory
and then write to it.
#include <stdio.h>
int main (void)
{
char *p;
unsigned int i;
p = malloc (100000000);
while (1)
{
for (i=0;i<100000000;i++)
*(p+i) = 5;
sleep (1);
for (i=0;i<100000000;i++)
*(p+i) = 6;
sleep(1);
}
}
I can run 9 copies of this program to take up 900M of memory. When
I attempt to start the 10th process, the whole world goes nuts. The
X-window that it was started in closes and I continue to get a
signal 11 interrupt whenever I run a shell command or attempt to compile.
I have another program that will allocate ~2GB of memory and then write data to
it. It attempts to read the data back and fails around the 850-900M mark.
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
int main (void)
{
int done = 0;
unsigned int i = 0x7feee800;
char *p;
char *p2;
unsigned int x;
p = malloc(i);
sleep (1);
for (x=0;x<i;x++)
{
*(p+x) = 5;
if (*(p+x) !=5)
{
printf("first Error %x %x Address = %x \n", p, x, p+x);
free(p);
return (0);
}
}
for (x=0;x<i;x++)
if (*(p+x) !=5)
{
printf("5 Error %x %x Address = %x Value = %x \n", p, x, p+x, *(p+x));
free(p);
return (0);
sleep(1);
}
memset(p, 10, i);
for (x=0;x<(i-1);x++)
if (p[x] !=10)
{
printf("A Error %i %x\n", p[x], x);
/* free(p);
return (0);*/
}
printf("Done\n");
free(p);
return (0);
}
--------------------------
Example Run Result:
5 Error 4010f008 32650ff8 Address = 72760000 Value 67
------------------------
The failing address is always a multiple of 0x10000.
Could you give me some info on what I am doing wrong?
Thanks for your time,
Dave
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This archive was generated by hypermail 2b29 : Mon Apr 23 2001 - 21:00:38 EST