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Normally, read and write system calls
should not account for more than half of the total number
of system calls.
If the number of characters transferred
by each read (rchar/s / sread/s)
or write (wchar/s / swrit/s)
call is small, it is likely that some applications are
reading and writing small amounts of data for each system call.
It is wasteful for the system to spend much of its time switching
between
system
and
user mode
because of the overhead this incurs.
It may be possible to reduce the number of read and write calls by tuning the application that uses them. For example, a database management system may provide its own tunable parameters to enable you to tune the caching it provides for disk I/O.