whatsnew-may14,1997

Linux磁盘测试的源代码,测试磁盘的读写性能

May 14, 1997 by Robin Miller

	The following changes have been made to 'dt' Version 10.8:

     o	Ali Eghlima added a "munsa={cr,pr,cw,pw,ex}" options which
	uses DLM for MUNSA testing.  Here's the 'dt' help text:

     MUNSA Lock Options:
        cr = Concurrent Read (permits read access, cr/pr/cw by others)
        pr = Protected Read (permits cr/pr read access to all, no write)
        cw = Concurrent Write (permits write and cr access to resource by all)
        pw = Protected Write (permits write access, cr by others)
        ex = Exclusive Mode (permits read/write access, no access to others)

            For more details, please refer to the dlm(4) reference page.

     o	If a "skip=" count is specified with an output file "of=",
	open the file for R/W access since skips are accompished via
	read()'s of record size.
	[ Per Olov Wahlstrom reported this problem. ]

     o	If a copy or verify operation is selected, and a data limit
	is specified, then double the data limit to account for double
	the I/O's.  Previously, only half of the desired data limit was
	copied and/or verified.

     o	Check status from closing file descriptor, and if it's not
	SUCCESS, use this for the exit status.  For tapes, deferred
	writes and failure to write file marks occur at close time.
	[ Roger Richardson reported this problem. ]

     o	If we encounter a ENOSPC error and no data has been transferred,
	flag this as an error.  This normally indicates a zero length
	partition or the user may have seek'ed past eom or eop.
	[ George Bittner reported this problem. ]

     o	Removed use of undocumented AIO_SEEK_CUR in aio_offset.
	Also fixed bug where random I/O offset was clobbered, thus
	resulting in sequential I/O.
	[ Jeff Denham reported this problem. ]

     o	Report number of I/O's per second (some people desire this).

	The latest version of 'dt' is available on our production machines
in the following account:

		Location: wasted:~rmiller/dt.d/{dt-ptos,dt-dlm,dt-V3.2}
				or via
		URL: http://www.zk3.dec.com/~rmiller/dt.html

Cheers,
Robin
================================================================================
	This example shows the new handling of ENOSPC error code:

% dt of=/dev/rrz2b position=393216b records=1 disable=verify
dt: 'write' - No space left on device
dt: Error number 1 occurred on Wed May 14 14:27:45 1997
Total Statistics:
     Output device/file name: /dev/rrz2b (Device: RZ25, type=disk)
        Data pattern written: 0x39c39c39 (read verify disabled)
     Total records processed: 0 @ 512 bytes/record (0.500 Kbytes)
     Total bytes transferred: 0 (0.000 Kbytes, 0.000 Mbytes)
      Average transfer rates: 0 bytes/sec, 0.000 Kbytes/sec
     Number I/O's per second: 0.000
      Total passes completed: 1/1
       Total errors detected: 1/1
          Total elapsed time: 00m00.03s
           Total system time: 00m00.01s
             Total user time: 00m00.00s
               Starting time: Wed May 14 14:27:45 1997
                 Ending time: Wed May 14 14:27:45 1997

% echo $status
-1
% 

================================================================================
	This example shows the "Number I/O's per second" addition:

im2fast% dt of=/var/tmp/dt.data bs=8k limit=25m
Write Statistics:
     Total records processed: 3200 @ 8192 bytes/record (8.000 Kbytes)
     Total bytes transferred: 26214400 (25600.000 Kbytes, 25.000 Mbytes)
      Average transfer rates: 2021676 bytes/sec, 1974.293 Kbytes/sec
     Number I/O's per second: 246.787
      Total passes completed: 0/1
       Total errors detected: 0/1
          Total elapsed time: 00m12.96s
           Total system time: 00m00.95s
             Total user time: 00m01.70s

Read Statistics:
     Total records processed: 3200 @ 8192 bytes/record (8.000 Kbytes)
     Total bytes transferred: 26214400 (25600.000 Kbytes, 25.000 Mbytes)
      Average transfer rates: 4239526 bytes/sec, 4140.162 Kbytes/sec
     Number I/O's per second: 517.520
      Total passes completed: 1/1
       Total errors detected: 0/1
          Total elapsed time: 00m06.18s
           Total system time: 00m00.61s
             Total user time: 00m05.50s

Total Statistics:
     Output device/file name: /var/tmp/dt.data
   Data pattern read/written: 0x39c39c39
     Total records processed: 6400 @ 8192 bytes/record (8.000 Kbytes)
     Total bytes transferred: 52428800 (51200.000 Kbytes, 50.000 Mbytes)
      Average transfer rates: 2737796 bytes/sec, 2673.629 Kbytes/sec
     Number I/O's per second: 334.204
      Total passes completed: 1/1
       Total errors detected: 0/1
          Total elapsed time: 00m19.15s
           Total system time: 00m01.56s
             Total user time: 00m07.20s
               Starting time: Wed May 14 15:45:18 1997
                 Ending time: Wed May 14 15:45:37 1997

im2fast% 

==============================================================================