cached - monitor single bit secondary cache errors.
cached [-s size] [-S delay] [-fC] [-p priority]
cached monitors the number of single bit errors in the secondary cache of
each cpu. It reports the number of single bit errors encountered on any
cpu each time it runs.
The -s size parameter determines the size of the cpu secondary cache in
bytes. If no value is specified, the default value of 4194304 (4 MB) is
The -S delay parameter indicates the amount of time to wait each time
between examining the secondary caches. This delay is in seconds and the
default is 3600 seconds (one hour). The -C option must be used for this
option to mean anything useful.
The -p priority parameter indicates the priority cached will be run at.
The value can be in the range -20 to 20 with -20 being the highest
priority and 20 being the lowest. The priority defaults to 10.
The -f parameter indicates that cached should run on all enabled cpus.
Normally cached does not run on restricted cpus.
The -C parameter indicates that cached should run continuously, sleeping
and running the check of secondary caches forever. If this option is not
specified, the program runs once and then exits.
cached uses the R10000 performance registers at the user level to monitor
the number of single bit cache errors. Single bit errors are
automatically corrected by the hardware. If the secondary cache has
numerous single bit errors, there is a possibility that these could turn
into multi-bit errors which are fatal for the system. Monitoring the
number of single bit errors provides a means of warning the user early
enough so that the cpu module containing the cache may be replaced.
cached runs at a very low priority by default so as not to interfere with
the normal usage of the machine.
cached is run as a cron job and can be turned off or controlled using the
To avoid disruptions to real-time usage, cached normally does not run on
isolated or restricted cpus. This can be overridden by using the -f flag.
/usr/diags the diag user's home directory
/usr/diags/bin/cached location of cached executable
/usr/diags/bin/diagsetup script to control the periodic running of
testfpu and cached
This command works only on MIPS R10000 systems.
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