January 28, 1998 Robin Miller
The following changes have been made to 'dt' Version 10.12:
o Add dtaio_close() function, to wait for queued I/O's when we're
aborting, to avoid kernel I/O AIO rundown problem, which panic's
the system if we close the CAM disk driver device descriptor,
prior to AIO's completing (fixed in steelos by Anton Verhulst).
[ Refernce QAR Number 57040 for more information. ]
NOTE: This problem is very prevalent when doing "cable pulls"
or otherwise forcing CAM disk I/O's into error recovery
and then aborting running 'dt's. This I/O waiting only
occurs once, as a 2nd signal (i.e. "kill" or <Ctrl/C>
simply exits the program. Beware of "kill -9" :-)
o Don't initialize data buffer being written for "disable=compare"
which yields better performance. Also correct a problem referencing
memory map (mmap) data due to compiler optimization (reference_data()
use static volatile). [ Changes requested by Marcus Barrow, thanks! ]
The latest version of 'dt' is available on our production machines
in the following account or from my web page, shown below:
Location: wasted:~rmiller/dt.d/{dt-ptos,dt-dlm,dt-V3.2}
or via
URL: http://www.zk3.dec.com/~rmiller/dt.html
NOTE: DLM version of 'dt' hasn't been recompiled yet!
Cheers,
Robin
================================================================================
im2fast% dt if=/dev/rrz0c iotype=random disable=compare runtime=3m enable=debug aios=250
dt: Attempting to open input file '/dev/rrz0c', mode = 00...
dt: Input file '/dev/rrz0c' successfully opened, fd = 9
dt: Data limit set to 1050040320 bytes, 2050860 blocks...
dt: Allocated buffer at address 0x14002e000 of 516 bytes, using offset 0
dt: Allocated buffer at address 0x140030000 of 516 bytes, using offset 0
dt: Allocated buffer at address 0x140034000 of 516 bytes, using offset 0
.
.
.
[ <Ctrl/C> entered here to abort test... ]
Total Statistics:
Input device/file name: /dev/rrz0c (Device: RZ26B, type=disk)
Data pattern read: 0x39c39c39 (data compare disabled)
Total records processed: 1080 @ 512 bytes/record (0.500 Kbytes)
Total bytes transferred: 552960 (540.000 Kbytes, 0.527 Mbytes)
Average transfer rates: 35829 bytes/sec, 34.989 Kbytes/sec
Number I/O's per second: 69.978
Total passes completed: 0
Total errors detected: 0/1
Total elapsed time: 00m15.43s
Total system time: 00m00.08s
Total user time: 00m00.01s
Starting time: Wed Jan 28 10:17:32 1998
Ending time: Wed Jan 28 10:17:48 1998
dt: All requests completed before cancel...
dt: Closing file '/dev/rrz0c', fd = 9...
im2fast%
