RE: malloc and threads

["Mathew, Tisson K" <tisson dot k dot mathew at intel dot com>]

Thanks Wolfram,

Sorry for missing the header files, it was a cut-paste error. I have seen it
running without any problems for a longer time with 100msec sleep,
eventually it will seg fault but without the sleep it seg faults sooner both
times the seg fault is at either chunk_alloc or chunk_free (I have made the
sleep to one iteration of the for loop in the code below). Apparently it
works fine if I add mutex around malloc and free. 

XScale is an ARM based processor ( http://www.intel.com/design/intelxscale/
)I'm running a XScale Linux ( Kernel Version 2.4.7 ) distribution from
LynuxWorks (http://www.lynuxworks.com/products/bluecat/bluecat.php3) & glibc
2.2.2 and Linux Kernel Dev for ARM is maintained by Russell King (
http://www.arm.linux.org.uk ).

-------------------------------------------------------------
#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>

#define MYSIZE                          (1*1024)
#define SLEEP_TIME                      (100*1000) // usec

void *AllocThread(void *pvArg);

int main(int argc, char **argv)
{
  pthread_t hThread;
  int       ii;
  int       iLimit=12;

  for(ii=0;ii<iLimit;ii++)
    pthread_create(&hThread,NULL,AllocThread,NULL);

  AllocThread(NULL);

  return 0;
}

void *AllocThread(void *pvArg)
{
  struct timeval tv{0,SLEEP_TIME}; /*sleep only at the first iteration */
  char          *pBuff=NULL;

  for(;;)
    {
      if((pBuff=(char *)malloc(MYSIZE))==NULL)
        printf("Could not alloc in parent!\n");
      else
        memset(pBuff,0x05,MYSIZE);

      select(0,NULL,NULL,NULL,&tv);
      if(pBuff)
        free(pBuff);
    }

  return NULL;
}

/* compile: gcc -o malloc_test malloc_test.c -l pthread */

------------------------------------------------------------

thanks
-tisson

-----Original Message-----
From: Wolfram Gloger [mailto:Wolfram.Gloger@dent.med.uni-muenchen.de] 
Sent: Wednesday, November 27, 2002 5:37 AM
To: tisson.k.mathew@intel.com
Cc: libc-alpha@sources.redhat.com
Subject: Re: malloc and threads


Hello,

> Here is the code; I'm running glibc 2.2.2 on XScale iq80320. 
> 
> -------------------------- 
> #define MYSIZE                          (1*1024)
> #define SLEEP_TIME                      (100*1000) // usec
> 
> void *AllocThread(void *pvArg);

After adding

#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>

and compiling with -pthread, I am able to run this test successfully
for hours, on ix86 with glibc-2.2.5.  Same on an old system with
glibc-2.1.3 on it.

Sorry, I have no idea what an "iq80320" is.

Regards,
Wolfram.