Hi,

I have a system running a 2.4.19 kernel with dasd,c at revision 1.234.2.40.    
I have a question about /proc/dasd/statistics, in particular the queue depth 
data.

http://oss.software.ibm.com/linux390/perf/tuning_how_tools.shtml  show example 
queue stats and says that # of req in chanq at enqueue (1..32) - each 
subchannel the DASD driver has a 5-deep queue.    When I look at the dasd.c 
at the above revision it seems to me that the subchannel queue is a linked 
list whereby statistics are only logged for the first 32 queue positions.

Am I missing something?

The reason I ask is because I have data like....

81076 dasd I/O requests
.
.
.
# of req in chanq at enqueuing (1..32)
� 16773 � �3814 � �2578 � �2008 � �1766 � �2813 � �1169 � �1013 � � 839 
731 � �1201 � � 540 � � 499 � � 479 � � 462 � � 889
� � 436 � � 431 � � 417 � � 412 � � 810 � � 400 � � 380 � � 336 � � 304
580 � � 285 � � 284 � � 281 � � 278 � � 550 � � 275

which seems to tie in with the code counting stats to a queue depth of 32.... 
but ... does this mean that I have approx 37000 i/o's going to a queue depth 
greater than 32??   That's approx 45%

Any thoughts?

Cheers
Geoff

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