Messages in this thread | | | Date | Mon, 26 Jul 1999 20:37:26 -0700 (PDT) | From | Gerald Aigner <> | Subject | Re: (disk/cpu) kernel performance problem |
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On Mon, 26 Jul 1999, Mark Lord wrote:
> Gerald Aigner wrote: > .. > > Looking into the problem I found that reading large data blocks from > > two IDE disks with the read(2) library/system call consumes about 45% > > of the available CPU time when reading roughly 30 Mbytes/sec. > ... > > Percentage of CPU time is not a useful measurement. > Think about it.. if I/O were infinitely fast, then CPU usage > would be 100%, since the CPU would never have to wait. > > If disk I/O were infinitely slow, CPU usage would be 0%, > but that's not a Good Thing, is it.. > 45% is the amount of time the kernel spends in loading data from disk.
The lower this value the more time is available for other threads/applications on the same system therefore increasing overall system utilization.
-Gerald
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