RCIM User’s Guide
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Refer to the
Available Configuration Options
section of the
rcim(4)
man page for
complete details on RCIM configuration.
General Considerations
1
When configuring the RCIM systems, keep the following in mind:
•
For a chain of RCIMs, the tick clock and POSIX clock in all slave RCIMs
will be synchronized with the master because the clock signal incrementing
time in the master is broadcast to all slaves. Once the clocks on all RCIMs
are initially synchronized they will remain synchronized.
To synchronize tick clocks, a working TCP/IP connection between all
systems is needed. In addition, each slave RCIM hostname configuration
must be set to the master RCIM, and each slave must be configured to run
the
rcim_clocksync
init script once on boot. This is only required if
your application is using the tick clock for synchronization.
System timekeeping daemons can be used to synchronize the POSIX
clocks, however there is a better mechanism:
rcimdate
(8). The RCIM-
master broadcasts its POSIX time down the RCIM cabling once per
second;
rcimdate
uses this to make the slave POSIX clocks exactly
match the master. This has several advantages over system timekeeping
daemons because no TCP/IP connections between systems are required,
synchronization is faster, and synchronization is extremely accurate.
•
Interrupts, whether operating locally or distributed across an RCIM chain,
will be processed according to the values configured on each system. If you
wish them to function in a manner different from established defaults, the
desired configuration options must be specified.
•
When distributing interrupts across the systems in an RCIM chain, all
systems must have a compatible configuration for the distributed interrupt
lines.
MSI Interrupt Configuration
1
RCIM IV and the latest versions of RCIM III (revision 9 and later) support MSI (message
signaled interrupts). By default, the RCIM kernel driver will initialize the hardware to use
MSI interrupts instead of PCI INTA interrupts whenever possible. By using MSI
interrupts, the RCIM is guaranteed of having its own non-shared interrupt, thus providing
more reliable interrupt response times.
The RCIM driver has an
rcim.nomsi=1
option which is independent of the
rcim=
configuration option described earlier. All versions of the driver have this option. If
specified the MSI capability is disabled on all RCIM boards that support it. There is no
mechanism to pick which boards are to be MSI-disabled and which ones are not. When
this option is specified, the RCIM driver will fallback to using the PCI INTA interrupt
method. For performance reasons, this option should only be used if a problem with MSI
interrupts is encountered.
Summary of Contents for RCIM
Page 1: ...Real Time Clock and Interrupt Module RCIM User s Guide 0898007 1000 March 2021...
Page 10: ...RCIM User s Guide 1 4...
Page 32: ...RCIM User s Guide 2 22...
Page 80: ...RCIM User s Guide A 28...
Page 102: ...RCIM User s Guide C 2...
