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From: vandana@MULTI.EE.USU.EDU (Vandana Rungta)
Newsgroups: comp.sys.transputer
Subject: I/O calls on the transputer.
Message-ID: <9007262052.AA01490@multi.ee.usu.edu>
Date: 26 Jul 90 20:52:06 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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	This I/O benchmark iocall.c was executed on different systems:

1) Sun 4/110
2) Sun 3/160
3) INMOS's T800 TRAM in a B411 module on INMOS's B014 transputer board using
   their parallel C compiler.

******************************************************************************

iocall.c

	Author:   Jan Stubbs, NCR, ..!sdcsvax!ncr-sd!stubbs

This benchmark tests speed of Unix system call interface and speed of cpu doing
common Unix io system calls.

Under normal circumstances, this benchmark will not actually cause any physical disk activity, but will just cause system buffer activity.


The source code for this benchmark:


#include <stdio.h>

char buf[512];
int fd, count, i, j;

main()
{
	fd = creat("/tmp/testfile",0777);
	close(fd);
	fd = open("/tmp/testfile",2);
	unlink("/tmp/testfile");
	for (i=0;i<=1000;i++) {
		lseek(fd,0,0);
		count = write(fd,buf,500);
		lseek(fd,0,0);
		for (j=0;j<=3;j++)
			count = read(fd,buf,100);
	}
	exit(0);
}

******************************************************************************
		
The results I got in terms of time taken on each system are:

1) Sun 4/110            0.067 sec
2) Sun 3/160            0.133 sec
3) T800 on B014        31.604 sec


Does anyone have any ideas as how to improve the performance on transputers?


Vandana Rungta         vandana@multi.ee.usu.edu