randy@chinet.chi.il.us (Randy Suess) (01/03/90)
Has anyone tried sadp on Interactive UNIX? I can't seem to find the magic incantation for the -d parameter. Tried all the /dev/dsk/h* etc. Thanks. -randy -- Randy Suess randy@chinet.chi.il.us
joe@junkyard.UUCP (Joseph Sarkes) (01/04/90)
It doesn't work on microport or esix either. Joseph Sarkes (junkyard!joe)
dwc@cbnewsh.ATT.COM (Malaclypse the Elder) (01/06/90)
i guess the problem is that as disk controllers got more intelligent, much of the statistics that were collected by the kernel couldn't be directly measured. the result is the implementers chose not to provide any measurements. one could provide approximations though. or do any of the disk interface specs (st506, esdi, scsi, etc) provide for obtaining performance measures directly from the controller? if they do, i could push for getting these measures in. danny chen att!hocus!dwc
pcg@aber-cs.UUCP (Piercarlo Grandi) (01/13/90)
In article <7088@cbnewsh.ATT.COM> dwc@cbnewsh.ATT.COM (Malaclypse the Elder) writes:
i guess the problem is that as disk controllers got more
intelligent, much of the statistics that were collected
by the kernel couldn't be directly measured. the result
is the implementers chose not to provide any measurements.
No. Most discs out there use very simple controllers, and even
SCSI controllers could be profiled easily by using block
numbers.
The real reasons why sadp is not supported are, in order of
importance:
1) most system administrators would not use it, because
they are lazy or not competent enough.
2) adding statiistics collection to a driver is an
extra job to do; if the customer does not ask for it,
it will be omitted.
3) In some cases statistics collection requires a table
whose size is combinatorial in the number of drives.
Point #3 is easy to obviate if statistics collection can be
disabled at system generation time. Points #1 and #3 are the
really important ones.
--
Piercarlo "Peter" Grandi | ARPA: pcg%cs.aber.ac.uk@nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth | UUCP: ...!mcvax!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk