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Tuning system call activity

Identifying excessive read and write system call activity

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.


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SCO OpenServer Release 5.0.7 -- 11 February 2003