sadp on i386
pcg at aber-cs.UUCP
Sat Jan 13 05:29:20 AEST 1990
In article <7088 at cbnewsh.ATT.COM> dwc at 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
The real reasons why sadp is not supported are, in order of
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 at nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth | UUCP: ...!mcvax!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg at cs.aber.ac.uk
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