[PTLsim-devel] why there is diference between cycles???

Tue Oct 23 01:28:08 EDT 2007

Dear all,

I have successfully run PTLsim in my computer. my OS is Fedora 6 and gcc
is 4.1.2 and the kernel of my computer is 32bits.
First, I set the options in the .conf file, as the following,
-stats test.stats -trigger

then, I using gcc get the binary excution code, test. all is fine,
but I got different clock cyclyes of the program running.
The first time , the result as following,

[user at EMBED ptlsim]$ ./ptlsim ./test
copy_args_env_auxv: Disabled 32-bit AT_SYSINFO auxv
copy_args_env_auxv: Disabled 32-bit AT_SYSINFO auxv
//  
//  PTLsim: Cycle Accurate x86 Simulator (32-bit version)
//  Copyright 1999-2007 Matt T. Yourst <yourst at yourst.com>
// 
//  Revision 225 (2007-09-22)
//  Built Oct 22 2007 11:26:32 on  using gcc-4.1
//  Running on EMBED.(none)
//  
//  Arguments: ./test
//  Thread 726 is running in 32-bit x86 mode
//  

Switching to simulation core 'smt'...
Stopping after 9223372036854775807 commits

Stopped after 42881 cycles, 29909 instructions and 0 seconds of sim time
(0 Hz sim rate)

The cycles is 42881, and then I run it again, the result as following:

[user at EMBED ptlsim]$ ./ptlsim ./test
copy_args_env_auxv: Disabled 32-bit AT_SYSINFO auxv
copy_args_env_auxv: Disabled 32-bit AT_SYSINFO auxv
//  
//  PTLsim: Cycle Accurate x86 Simulator (32-bit version)
//  Copyright 1999-2007 Matt T. Yourst <yourst at yourst.com>
// 
//  Revision 225 (2007-09-22)
//  Built Oct 22 2007 11:26:32 on  using gcc-4.1
//  Running on EMBED.(none)
//  
//  Arguments: ./test
//  Thread 728 is running in 32-bit x86 mode
//  

Switching to simulation core 'smt'...
Stopping after 9223372036854775807 commits

Stopped after 43157 cycles, 29909 instructions and 0 seconds of sim time
(0 Hz sim rate)

Oh, the cycles is 43157, not 42881, why?? I got the native frequencies
from the above test.stats files, both of them are 2992000000. would you
like to help clear the difference between cycles. 

BTW, If I want to get the high accurate run time, I use the cycles
number 43157/2992000000 (the native frequency) =  14.424131016
mircoseconds. Is it right??

Any suggestions from you are greatly appreciated. Thanks.

Best wishes,
Peter

P.S. my test program as following:
#include <stdio.h>
#include <sys/time.h>
#include <time.h>
#include "./../ptlcalls.h"
void run(int* pData,int left,int right)
{
 int i,j;
 int middle,iTemp;
 i = left;
 j = right;
 middle = pData[(left+right)/2]; //求中间值 
  do{
        while((pData[i]<middle) && (i<right))//从左扫描大于中值的数 
                       i++;
        while((pData[j]>middle) && (j>left))//从右扫描大于中值的数 
                       j--;
        if(i<=j)//找到了一对值 
                      {
                       //交换 
                        iTemp = pData[i];
                        pData[i] = pData[j];
                        pData[j] = iTemp;
                        i++;
                        j--;
                      }
}while(i<=j);//如果两边扫描的下标交错，就停止（完成一次） 

//当左边部分有值(left<j)，递归左半边 
if(left<j)
          run(pData,left,j);
//当右边部分有值(right>i)，递归右半边 
if(right>i)
          run(pData,i,right);
}
void QuickSort(int* pData,int Count)
{
 run(pData,0,Count-1);
}
int main(int args, char**argv)
{
        int i=0;
        //linStart = ((long long)(tvStart.tv_sec)) * 1000000 +
tvStart.tv_usec;
        ptlcall_switch_to_sim();
        for(; i<10; i++){
//      ptlcall_switch_to_sim();
         int data[] = {10,9,8,7,6,5,4, 12, 8, 87, 57, 49, 54, 7,6, 94,
57, 61, 31, 13, 25, 78, 69};
         QuickSort(data, 23);
        }
        ptlcall_switch_to_native();
/*      gettimeofday(&tvEnd, NULL);
        linEnd = ((long long)(tvEnd.tv_sec))*1000000 + tvEnd.tv_usec;

//      printf("completed\n");
        printf("%10ld micro-seconds\n", (linEnd-linStart));
//      }
//      else
//              printf("error\n");*/
        return 0;
 }